Lord Tebbit has said Gordon Brown's move to be seen as "heir to Thatcher" shows his "political nous".
The ex-Tory chairman said it was the "perfect response" to David Cameron's attempts to become the 'heir to Blair'.
He rejected any suggestion Baroness Thatcher, 81, had been exploited by the PM in making her visit to No 10, saying she knew "exactly what she was doing".
Lord Tebbit also told The Times many voters would think Mr Cameron did not know "how the other half lives".
Following the comment a Conservative Party official said: "We obviously don't agree with him. David Cameron and the Conservative Party have the answers to the challenges facing modern Britain."
Lord Tebbit said he had "considerable regard" for Mr Brown, saying the invitation to Lady Thatcher was "Gordon Brown at his very best; a wonderful mixture of his courtesy and his political nous".
"After all, Cameron described himself as the 'heir to Blair', it's only natural that Brown should make himself the 'heir to Thatcher'. It's the perfect response, isn't it?"
One Conservative MP, Rob Wilson, suggested that the "frail" former prime minister had been "exploited" by Mr Brown.
But Lord Tebbit said he was sure Lady Thatcher knew "exactly what she was doing" and accused the current Conservative leader of being "at great pains to distance himself from her".
He also said Mr Cameron and his fellow Old Etonian colleagues were "intellectually clever but they have no experience of the world whatsoever".
"He has spent much of his time in the Conservative Party and as a public relations guy. Well it's not the experience of most people in the streets.
"That's the real attack and that's damaging to him, I think," he said.
Mr Brown has been criticised for inviting Lady Thatcher to tea
Lady Thatcher, who was prime minister between 1979 and 1990, has visited each of her successors at Downing Street - John Major, Tony Blair and Mr Brown.
But her arrival at Downing Street two weeks ago followed Mr Brown's recruitment of several opposition party MPs, and one Tory donor, as advisers - and the defection of Tory MP Quentin Davies to Labour.
Mr Brown says he wants a new, inclusive type of politics.
But he has been accused of "deeply cynical" manoeuvring by Tory former foreign secretary Sir Malcolm Rifkind and by Lib Dem Treasury spokesman Vincent Cable as an attempt to create "a one party state".
Some Labour MPs were irritated by Mr Brown's praise for Lady Thatcher as a "conviction politician" and the invitation to Downing Street was described as a "huge political mistake" by GMB union chief Paul Kenny.