Melanie Onn

MP for Great Grimsby and Cleethorpes

Labour

Melanie Onn is the Labour MP for Great Grimsby and Cleethorpes, having returned to parliament at the 2024 general election. She previously served as the MP for the predecessor constituency of Great Grimsby between 2015 and 2019.

In the 2024 general election for the Great Grimsby and Cleethorpes constituency, Onn received 15,336 votes, representing 41.9% of the vote share. The Reform UK candidate, Oliver Freeston, came second with 10,533 votes (28.8%), while the Conservative candidate, Lia Nici, secured 8,269 votes (22.6%). Onn was duly elected with a majority of 4,803.

The Great Grimsby and Cleethorpes constituency is located in Lincolnshire.

Onn’s immediate predecessor MP for the Great Grimsby area was the Conservative politician Lia Nici. Onn was defeated by Nici at the 2019 general election.

Political Career

Onn is a member of the House of Commons energy security and net zero committee (since march 2025). The committee scrutinises the work of the Department for Energy Security and Net Zero.

Onn is also an elected parliamentary representative on the Labour Party National Executive Committee (NEC) (since September 2024).

At the beginning of the parliament elected in 2024, Onn stood unsuccessfully for election as chair of the energy security and net zero committee. In the contest, the results of which were announced in September 2024, Onn secured 253 votes, placing second. They were ultimately defeated by Bill Esterson, who won the support of 300 colleagues.

During her previous stint in parliament, Onn held several opposition frontbench positions. She was shadow minister for housing from July 2017 to March 2019.

Onn resigned from the frontbench in March 2019. She stepped down in order to vote against a confirmatory or second Brexit referendum, defying the Labour whip in the process. The motion was tabled by veteran Labour MP Margaret Beckett during a round of Brexit “indicative votes”.

Setting out her decision to resign, Onn told the Grimsby Telegraph: “I think there is an expectation in Grimsby that, ‘We told you what we wanted, now get on with it’. Grimsby is a proudly rebellious town – it doesn’t mind being out on its own.”

She added: “If we did hold another vote, the motion said it would be a ‘yes’ or ‘no’ on the deal agreed in the House of Commons.

“But if the public reject it and say no, then does the deal come back to parliament? Do we try again and then there is another public vote on something different, even though we don’t know what people didn’t like about it in the first place?

“I would prefer it if people who want to stop Brexit from happening wouldn’t hide behind a second referendum. They should just come out and say they want to revoke Article 50.”

Onn was shadow deputy leader of the House of Commons alongside Chris Bryant from September 2015 to June 2016.

In June 2016, Onn was among those to resign from the shadow frontbench in protest at Jeremy Corbyn’s leadership and his approach to the Brexit referendum.

Onn has sat as a member of the House of Commons committee on standards (2024-2025), the committee of privileges (2024-2025), the procedure committee (2016-2019), the housing, communities and local government committee (2016-2017) and the energy and climate change committee (2015-2015).

Onn lost her Great Grimsby at the 2019 general election, The Conservative candidate, Lia Nici, won 18,150 votes (54.9%) and a majority of 7,331 over Onn in second place.

Onn later said that Corbyn did not acknowledge her when she returned to parliament.

In the days following the election, Onn told ITV’s Peston programme: “He did walk past me yesterday at Portcullis House, slowed down and did a double take and carried on.”

Following her 2019 election defeat, Onn served as deputy chief executive of RenewableUK from February 2020 to January 2023.

Onn is a member of the all-party parliamentary groups (APPGs) on fisheries and kinship chair.

Onn delivered her maiden speech on 1 June 2015 during a debate on Britain’s place in the world.

In it, she stated: “Our future clearly lies in the prospects of a strong renewable energy sector, in partnership with our European neighbours. There is now an opportunity to draw more businesses to an additional port and to the port complex along the south bank, and that brings with it the hope of 4,000 new jobs.”

She added: “If, as so many in the town hope, we are to take Great Grimsby forward and truly become a 21st century port town, political support for the renewables industry is essential.”

Political Views

Leadership elections and loyalty

Labour leadership 2015: Onn nominated Yvette Cooper for the party’s leadership in June 2015. The election followed the resignation of Ed Miliband after the party’s defeat in the 2015 general election. It was the first contest held under the “one member, one vote” system, which replaced the previous electoral college.

Cooper, the shadow home secretary, secured 59 nominations from the Parliamentary Labour Party (PLP), comfortably exceeding the 35 required to reach the final ballot. She ultimately finished third in the contest with 17% of the vote.

Corbyn loyalty list: In March 2016, Onn was labelled as “hostile group” by the Corbyn leadership in a leaked list which categorised Labour MPs by their perceived loyalty. This label suggested the Corbyn leadership viewed Onn as actively and openly antagonistic.

Labour leadership 2016: Onn was one of 162 Labour MPs who nominated Owen Smith for the party’s leadership in July 2016. The election was triggered by a challenge to Jeremy Corbyn following the EU referendum, which led to a wave of shadow cabinet resignations and a vote of no confidence supported by 172 MPs. Smith, the former shadow work and pensions secretary, was ultimately defeated by Corbyn, who won with an increased mandate of 61.8% of the vote.

Factional identity and party tradition

Tribune group (2017): Onn was listed among the supporters of the Tribune parliamentary group – a caucus generally described as representing the party’s “soft left”.

The Tribune group was initially formed in 1964 to support the newspaper of the same name. It served as a prominent forum for those parliamentarians situated on the left of the Labour Party – but it split over Tony Benn’s campaign for the deputy leadership in 1981. Benn’s supporters founded the Campaign group – which evolved into the Socialist Campaign Group (SCG). Today, the Bennite SCG is strongly associated with the Labour left tradition.

During the 1980s, the Tribune group emerged as a more natural home for those on Labour’s “soft left”.

In 2017, Efford officially re-launched the group with a new mission statement calling for “opportunity and aspiration” to be placed at the heart of the party’s programme. Efford said he had reformed the group to ensure that the centre-left of the Parliamentary Labour Party (PLP) “have a space in which to put forward ideas and debate which has not been there under successive leaders”.

He added: “The view of Labour MPs at the moment tends to be that too much are just Blairites who want to stab Jeremy Corbyn in the back. We want to show that is not where we are, and that we want to develop our own ideas that represent the centre-left of the party.”

Brexit and Europe

Brexit referendum: Onn supported Remain in the 2016 Brexit referendum, and therefore disagreed with a majority of her constituents, 71.4% of whom voted to Leave.

Article 50: In February 2017, Onn voted in favour of the European Union (Notification of Withdrawal) Bill. The legislation empowered the prime minister to notify the Council of the European Union of the UK’s intention to withdraw, formally triggering the process set out in Article 50 of the Treaty on European Union. MPs supported the bill by 498 votes to 114 at second reading.

Welfare

Welfare ‘reasoned amendment’ (June 2025): Onn was one of the over 120 Labour MPs to sign the reasoned amendment to the government’s flagship welfare bill which aimed to reject the proposed legislation.

The amendment, in the name of senior Labour MP Dame Meg Hillier, objected to the fact that the bill had not been subject to a “formal consultation with disabled people” and that “250,000 people will be pushed into poverty” as a result of it, according to a government impact assessment.

The motion also called on the government to wait for the publication of the review into the Personal Independence Payment (Pip), helmed by minister Sir Stephen Timms, and the independent review, conducted by Sir Charlie Mayfield, into how the employment of disabled people could be boosted.

Welfare vote (July 2025): Onn voted in favour of the government’s flagship welfare bill at second reading. The vote came after ministers agreed to significant concessions to avoid defeat via a mass rebellion of Labour MPs on 1 July 2025.

Assisted dying

Onn voted in favour of the Terminally Ill Adults (End of Life) Bill, better known as the assisted dying bill, at second reading (November 2024) and third reading (June 2025).

Social values and conscience issues

Abortion decriminalisation (2025): Onn voted in favour of a backbench amendment to the Crime and Policing Bill that sought to decriminalise abortion in England and Wales in June 2025. The amendment, which was passed by a majority of 242 votes, removed women from the threat of prosecution for ending a pregnancy at any stage. As an issue of conscience, MPs were allowed to vote according to their personal beliefs.

Foreign policy and security

Trident renewal (2016): Onn voted in favour of a government motion calling for the renewal of the Trident nuclear deterrent system in July 2016. The motion, which was passed by 472 votes to 117, committed the UK to constructing a new fleet of submarines to carry the nation’s nuclear weapons. Labour was split over the issue with 140 of its 230 MPs going against leader Jeremy Corbyn and backing the motion.

Syria airstrikes (2015): Onn voted against a government motion to extend UK airstrikes against Isis from Iraq into Syria in December 2015. The motion, which was passed by 397 votes to 223 after a ten-hour debate in the House of Commons, authorised the RAF to conduct strikes against Isis targets in Syria.

Before Politics

Born on 19 June 1979 in Grimsby, Onn grew up in the town on the Nunsthorpe and Grange housing estates.

She attended Healing School and Franklin College. At the age of 17, she sought assistance from Doorstep, a charity providing housing support to young people.

Onn studied at the University of Middlesex, graduating with a degree in politics, international studies and philosophy.

Before her election to parliament, Onn worked at the Labour Party’s head office for 10 years.

From 2010, she worked as a regional organiser for the trade union Unison. She also stood unsuccessfully as a Labour candidate for the Yorkshire and Humber region in the 2009 European Parliament elections.