The former foreign secretary Sir Malcolm Rifkind warned on Thursday night that Lord Lawson had thrown the equivalent of a "hand grenade into a small building" by calling for Britain to leave the EU.

In the first response to Lawson's intervention by a Tory grandee, the former foreign secretary accused the former chancellor of abandoning the legacy of Margaret Thatcher, and said Lawson wanted to place Britain in a "humiliating" position in which it would be subject to EU rules with no say in their implementation.

Rifkind, who sat in Thatcher's cabinet with Lawson for three years from 1986-89, said the former chancellor's call for Britain to part company with the "bureaucratic monstrosity" of the EU was a significant moment in Tory history.

In an interview with the Guardian, Rifkind said: "For someone of Nigel Lawson's stature to say that he has changed his position and now reached the view that the United Kingdom would be better off outside the EU – whether or not one agrees or disagrees with his judgment – that is the equivalent of throwing a hand grenade into a small building."

Rifkind, who said Lawson had failed to spell out in his Times article the new terms of Britain's relationship with the EU, said opponents of the EU appeared not to realise that the UK would still be subject to EU rules if it left and decided to remain in the single market. He cited Switzerland and Norway, which have access to the market but no say on its rules.

Rifkind pointed out that Lawson was instrumental in pressing for Britain to join the European exchange rate mechanism and likened his "humiliating" approach to that of SNP leader Alex Salmond's plans for an independent Scotland.

"For a very small country that may be unavoidable," he said of the relationship Norway and Switzerland have with the EU. "For a country the size of the UK that would be rather humiliating I would have thought.

"[It] is rather like what Mr Salmond is seeking to do in Scotland – we will continue to use the British pound even when we are an independent country. But we will have no influence over the monetary policy of the Bank of England. Well, if we are going to criticise Mr Salmond, as people rightly do, the same principle would apply if we were following a Norwegian or Swiss relationship with the EU."

Rifkind, who served as foreign secretary in John Major's government, said Lawson was wrong to say that David Cameron will only win "piffling changes" when he attempts to reform the EU if he wins the next election. Lawson said the prime minister would do no better than Harold Wilson ahead of the 1975 referendum.

The former foreign secretary said: "I find it very sad that people of the extraordinary calibre of Nigel Lawson should make such an assumption simply based on Harold Wilson's failed renegotiation in his particular day. Why can't he use Margaret Thatcher as a comparison rather than Harold Wilson?

"Nigel Lawson, of all people, should remember the position Margaret Thatcher was in when she sought to renegotiate our rebate with the rest of the European community," he said. "She was literally one contra mundum. It would have been perfectly reasonable for some people to argue at the time, what possible hope is there of the British government succeeding in persuading the rest of the EU – at their own expense – to rebate Britain billions of pounds for each year for the foreseeable future. And yet that was achieved."

Rifkind said he agreed with Lawson who warned that Brussels wants to impose damaging regulations on Britain's financial services. But he said he is confident that Cameron will be able to ensure Britain can block such proposals when he embarks on his renegotiation.

"Nigel Lawson is quite right to say there are some pretty silly proposals coming out of Brussels that would effect the city of London and UK financial services. I would stand four square with him in arguing that part of David Cameron's renegotiating shopping basket should be to ensure that any proposals for the financial services sector – the fact that the UK has about 60% of all the financial services in the EU must mean that new proposals in that sector should not be able to take effect unless the UK is willing to go along with that, is able to be part of that consensus."

Rifkind said he believes the prime minister will succeed because Angela Merkel recently invited Cameron and his family to her country retreat and had said she would consider his EU speech, in which he pledged to hold a referendum by 2017, with care. "It is grossly premature to assume that the prime minister's renegotiation will not succeed. I would go beyond that. the signs since his Bloomberg speech of the likely reaction of his European colleagues so far is positive rather than negative."