David Lidington defends Cameron's EU deal as he is grilled on Newsnight

Europe Minister David Lidington has defended David Cameron's EU deal, saying "this is a very good basis for a deal that delivers answers to things [about] which the British people had been most concerned." Lidington made the comments during an appearance on BBC's Newsnight in which he responded to remarks made by the prime minister that "hand on heart", he had delivered the commitments he made in the manifesto.

Cameron has faced widespread criticism over the offer by Brussels, which have been branded as "watered-down" by critics. Lidington acknowledged that while there is a "basis" for a good settlement, work remains to be done. Referring to the texts, Lidington said: "There are elements in it that are still in square brackets. There is still negotiation to be done – this is a deal that will require the agreement of all other 27 heads of government."

The prime minister had originally wanted to block migrants from sending child benefits abroad, but was unable to fully achieve that objective. Instead, child benefits can still be sent home, but receive an amount proportionate to the cost of living in that country. On the issue of child benefits, Lidington said: "If we get that [the deal on child benefits] as part of a broad overall package, then we think that would represent a reasonable compromise. We are looking at every aspect of this negotiation because the different parts all hang together."

Lidington faced tough questioning from Newsnight host Evan Davis, given the importance of the issue and Cameron's comments which have antagonised some Conservative MPs, who are threatening to defy the prime minister by publicly lambasting the EU deal. The Europe Minister was derided for his performance on the show, with Twitter users calling him "poor", "awful" and unable to answer "simple questions about the EU renegotiations".

Speaking to the Telegraph, one Cabinet source said: "The Prime Minister has fired the starting gun for the EU campaign and made clear he will be leading the charge to stay in. The assumption is that collective responsibility is over."

Anne-Marie Trevelyan, Conservative MP for Berwick-upon-Tweed said an opt-out from an ever-closer union – which was one of Cameron's four pillars – is critical. Speaking on Newsnight, Trevelyan said: "The response in the document is pretty feeble, as far as I can see. It says that they understand that that's what we're asking for and when they get to any future treaty, whoever is running those Member States then ... will have a look at it and see if they can roll it into a future treaty."