By Oliver Hotham
Government plans for an elected upper house could lead to the British National Party (BNP) gaining its first seats in parliament, according the Viscount Astor, the stepfather of the prime minister's wife Samantha.
The heredity peer said the plans were "cobbled together", and intended to appease the Liberal Democrats.
"Ukip could have more peers than the Lib Dems", he warned in a speech to the House of Lords.
He continued:"Ukip stand to gain most and, the rather frightening thought, the BNP might for the first time be represented in Westminster.
"One would have thought that was the very last thing the coalition would want."
He went on to describe the proposed reform as "heading for an almighty
Viscount Astor is among several senior peers voicing concerns about the government's proposals to introduce elected peers to the Lords by 2015.
Critics have claimed that the proposals could undermine the power of the House of Commons, arguing that the Lib Dems call for peers to be elected by proportional representation would hurt the Conservatives.
Peers are also arguing that the government has not sufficiently answered how power will be balanced between the Commons and the Lords, and what would happen in a deadlock situation.