David Cameron to face MPs in Commons over EU veto
Many of his own MPs in the Commons will welcome his decision, but Labour and some Lib Dem MPs are set to criticise Mr Cameron for isolating the UK.
Labour leader Ed Miliband will accuse Mr Cameron of failing in his objective of protecting the City of London.
The PM is expected to say why he felt his approach was in the UK's interest.
Downing Street sources told the BBC he would give a factual account of the decisions he took in Monday's statement.
Mr Cameron blocked changes to the EU's Lisbon Treaty, which were aimed at addressing the euro crisis and preventing a repeat in the future, at a summit in Brussels on Friday.
He and Chancellor George Osborne have insisted the veto was in part to protect the City of London from excessive intervention by Europe, but Labour and the UK Independence Party (UKIP) have both argued that actually no additional safeguards were achieved.
The treaty changes needed the support of all 27 EU members, including those not in the euro, such as the UK, to go ahead.
BBC political correspondent Iain Watson says Mr Cameron's decision to veto a new EU treaty without the protection he wanted for Britain's financial services industry will be welcomed by many Conservatives in the Commons, but he will not get unqualified support.
Some Conservative MPs will urge him to go further by bringing back powers from Brussels to the UK.
Lib Dem backbenchers, meanwhile, feel they have been given the green light to criticise Mr Cameron following Nick Clegg's warning about the outcome of the Brussels summit, our correspondent adds.
Initially Mr Clegg, the Lib Dem leader and Deputy Prime Minister in the coalition government, had said the coalition was united over the use of the veto, but on Sunday he said he had "made it clear" to Mr Cameron it was "untenable" for him to welcome a move that he saw as "bad for Britain"; Kazinform cites BBC.
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