By Ian Dunt
The starting gun for last-ditch coalition negotiations has been fired.
Gordon Brown made a statement outside Downing Street this afternoon saying the civil service would make arrangements for the Nick Clegg and David Cameron to meet.
"On the critical question on the formation of a government I have of course seen the statements of other party leaders," Mr Brown said.
"I understand and completely respect the position of Mr Clegg in saying he wants to make contact with the leader of the Conservative party. Mr Cameron and Mr Clegg should clearly be entitled to take as much time as they deem necessary."
The statement followed comments from Lib Dem leader Nick Clegg, in which he confirmed to reporters that he would abide by his election campaign pledge to first negotiate on a coalition with the party with the most popular support and parliamentary seats.
But Mr Clegg inserted a caveat into the commitment this afternoon, stressing that electoral reform was now a mandatory requirement of coalition agreements.
That requirement was directly addressed by Mr Cameron in a hastily arranged press conference in Westminster this afternoon, when the Tory leader said he would be prepared to discuss electoral reform.
"The Lib Dems have their ideas and we have our ideas," Mr Cameron said, before offering a parliamentary inquiry in to electoral reform. Mr Cameron was careful to stress that he believed in maintaining the constituency link but that there were other options which were worth considering.
The Tory leader said the two men could work together on green policy, pupil premiums and civil liberties, but he drew red lines on defence, immigration and Europe.
Mr Brown made clear he would be prepared to enter negotiations if talks between Mr Clegg and Mr Cameron break down.
"For my part, I would be ready to see any of the party leaders," he said.
"If the talks between Mr Clegg and Mr Cameron come to nothing I would be prepared to meet with Mr Clegg.
"I am willing to discuss with Mr Clegg, and there are significant areas of agreement," he went on.
"The first is the need for economic stability, the other is far-reaching political reform including that of our voting system.
"The people gave given us a strong message which must be heard.
"It is imperative that we have a strong stable government which can command the support of parliament in order to tackle the challenges ahead."
The dramatic statement came at the end of a day which saw protracted debate and rumours over which of the parties would be able to make a deal which could command the confidence of the Commons.
It is the first time Britain has returned a hung parliament since 1974.
Mr Cameron is due to make a statement at 14:30 BST.