DAVID Cameron has challenged the SNP and Alex Salmond to "keep their promise" and accept that the referendum result ended the independence question.

The Prime Minister made his challenge as the potential difficulty of banning Scottish peers from voting on English-only legislation was raised in the Lords when Lord Wallace, the Advocate General, noted how members of the Lords did not have constituencies like MPs but were "peers of the United Kingdom."

During Commons question time, Angus MacNeil, the SNP MP for the Western Isles, pointed out how before the referendum Mr Cameron had made clear that if there were a No vote, then all options on further devolution to Holyrood would be possible.

"So will he unequivocally stand by his promise and confirm this, of course, means full fiscal autonomy is on the table; meaning devolving full control of Scottish taxes and spending to the Scottish Parliament to help create jobs and a more just society?"

The PM - praising the work of Lord Smith in the Commission and saying he was sure it could find a way forward - insisted he stood by all the promises he had made in the run-up to the referendum campaign.

"But," Mr Cameron added, "on the basis of keeping our promises, I hope the SNP will keep their promise when they said that the referendum ended this question for a generation, possibly a life time. I'm not sure their former leader is sticking to that but he should."

In the Lords, Lord Palmer, a Scottish hereditary Crossbench peer, pointed to the issue of English votes for English laws (Evel) and asked if, under this proposal, Scottish MPs were banned from some debates would Scottish peers be too.

Lord Grocott asked if the UK Government's law officer was saying while it would be fine to have two categories of MPs, withdrawing voting rights on EVEL from Scottish MPs, there would be no question of having two categories of peers.He said: "That sounds suspiciously like wanting to have your cake and eat it."