David Cameron has indicated he may be willing to hold a referendum on reforming the House of Lords, ahead of the publication of a report that is expected to demand the public be given a say.

Speaking on BBC Radio 4's Today programme this morning, the prime minister said while he was not in favour of holding a referendum a public vote could not be ruled out.

"Personally I don't see it as a very compelling case - it would cost a lot of money," he said- pointing out that it has also been in all three main parties' election manifestos.

"But we live in a democracy. parliament is going to debate and discuss this. The committee is about to come and and say that a referendum would be a good idea so we don't rule it out.

"But we are only going to get Lords reform through if we all behave like reasonable, rational, sensible people."

While the leaderships of the three main parties are in favour of reform, there is widespread opposition on the Tory benches to change and the Labour Party has said it wants to see a referendum on the issue.

The joint committee on Lords reform is due to publish its long awaited report on Monday morning, and it is expected to recommend that the public be given a vote.

Cameron said he was firmly in favour of a mostly-elected second chamber which would "strengthen our parliament and strengthen the House of Lords" but accepted that it was not the Government's top priority.

"One of the reasons Lords reform never goes ahead is that, although there is a majority for it in the Commons and the three main political favours are in favour, all the parties are split on it. That is the fact.

"So the only way it can happen is if all the parties agree to work together, rationally, reasonably, sensibly on trying to deliver what I think the British public would see as, not a priority, but a perfectly sensible reform that we have people legislating in the House of Lords who are elected by right."