Tony Blair was branded the true heir of Margaret Thatcher yesterday by the former deputy Labour leader Lord Hattersley.

Lord Hattersley compared the Prime Minister unfav-ourably with Gordon Brown and said he was "astonished" the party had tolerated Mr Blair for so long. He warned that the gratitude Labour felt towards Mr Blair for regaining power was wearing off.

"He has done so much which is offensive to rank-and-file opinion that I think the worm is beginning to turn," he told GMTV's Sunday.

Lord Hattersley described Mr Blair as "much more the heir to Margaret Thatcher" than previous Labour leaders because of his belief in competition and the market – even in public services such as health, secondary education and universities. But he acknowledged that Mr Blair was "more compassionate" and more worried about the poor than Baroness Thatcher had been.

He predicted Mr Blair would resign immediately after winning a third general election rather than "push his luck".

Lord Hattersley said he hoped Mr Brown would succeed Mr Blair, but he warned that his prospects of doing so would be enhanced if he were loyal to the Prime Minister. "I would advise him not to do anything to precipitate that day," Lord Hattersley said. "I think he has to go on loyally supporting the Prime Minister and sometimes biting his lip when he disagrees with what the Prime Minister wants. That is the necessity of being the effective number two."

The remarks follow speculation that the relationship between Mr Blair and Mr Brown is at its lowest ebb and that the Chancellor is impatient to take over. Downing Street has denied Mr Brown asked Mr Blair when he would stand down.

Lord Hattersley said Mr Brown was a "very different political figure" to Mr Blair. "Gordon Brown and I talk the same language; our arguments are Labour Party arguments. With Tony Blair, the arguments are outside the Labour Party.

"I always say it's rather like my football club, which I've followed for 50 years, saying 'by the way, we're not playing football any longer, we're now playing hockey and we still expect you to turn up and support us.' Gordon is still playing football, Tony is playing hockey."