A veteran Labour MP who was first elected to parliament in 1966 has said members of his party should be free to criticise the "brutal contempt" with which Margaret Thatcher treated millions of working people.
MPs and peers will return to Westminster from the Easter recess on Wednesday as parliament is recalled to debate the death of the former prime minister.
In a blow to Ed Miliband, who has instructed his MPs to follow his lead in responding to Thatcher's death in a respectful manner, David Winnick said it would be "absolutely hypocritical" if parliament did not hear all sides of the late prime minister's legacy.
Winnick, the MP for Walsall North, said: "It would be absolutely hypocritical if those of us who were opposed at the time to what occurred – the mass unemployment, the poverty – were to remain silent when the house is debating her life. This will be an opportunity to speak frankly.
"Obviously when a person dies one regrets it. But what I do regret first and foremost is the immense harm, certainly in the West Midlands where deindustrialisation occurred.
"Even if it could be argued that some of it was inevitable, the manner in which it was done – the brutal contempt towards those who were innocent victims – was absolutely disgraceful."
The remarks by Winnick, who was elected MP for Walsall North in the 1979 election that brought Thatcher to power after serving as MP for Croydon South from 1966-70, shows that Miliband may be unable to control some of his MPs.
One source said: "It is possible to disagree, with respect. Ed Miliband has made his position clear. We expect people to take note of that."
John Bercow, the Speaker, will open proceedings at 2.30pm after deciding to recall the Commons. The Lords will also be sitting.
David Cameron will speak first in the Commons. Miliband and Nick Clegg, the deputy prime minister, will also speak before backbenchers pay their respects.
The Tory benches are expected to be packed as MPs line up to praise the Conservative party's most revered leader after Winston Churchill.
Labour, which had been nervous that its benches would appear sparsely attended by its MPs, is now confident of a good turnout.
The continuing impact of Thatcher, who resigned as PM nearly a quarter of a century ago, was highlighted when one of her closest friends at Westminster indicated that he thought Cameron insufficiently radical.
In an interview with the World at One on BBC Radio 4, the MP for Bournemouth West, Conor Burns, said he showed Thatcher a poll in a Sunday newspaper last November which put the Tories 9 points behind Labour.
Burns added: "She asked when the next election was, and I said it wasn't for another two and a half years and she said: 'That's not far enough behind at this stage.' She sort of took a view that to do things that were right did entail unpopularity until people saw that what you were doing was working and she always had confidence that what she was doing would work and coincide with the electoral cycle which is, despite the fact that she's been written up as this incredibly controversial, divisive figure, which is why she won three general elections and was in power for 11 and a half years."
Burns also said that at a reception for newly elected Tory MPs, Thatcher made clear her unease at Cameron forming a coalition with the Lib Dems.
"One colleague said to her: 'Of course, Lady Thatcher, we have gone into coalition with the Liberal Democrats.' She looked at him and raised her index finger, jabbed it at him and said: 'I have not gone into coalition with the Liberal Democrats.'
"She wanted to see a standalone Conservative government. She was a tribal Conservative to her fingertips."
In a blow to the Ukip leader, Nigel Farage, who is trying to position himself as the leader who best upholds Thatcher's legacy, Thatcher also made clear to Burns and other friends that she remained resolutely loyal to the Tory party.
"Margaret Thatcher was a Conservative all her career and died a Conservative. That doesn't mean she didn't have regard for those who have sympathy for Ukip.
"But she understood that only the Conservative party is the big enough vehicle to deliver the change she would have wanted to see in Europe and in Britain."
Winnick made clear he is prepared to be highly critical when parliament is recalled. "Everyone has agreed, supporter and foe, that by becoming the first female prime minister she made history," he said. "The two prime ministers who have made the greatest impact since 1945 were Clem Attlee and Margaret Thatcher.
"Thatcher would have opposed at the time everything the Labour government of 1945 started to do. Bringing about the welfare state – the NHS, national insurance – she would have looked upon it with absolute distaste.
"Attlee, though he would be rather surprised to be given the description, was the revolutionary. She was the foremost counter-revolutionary who tried to reverse so much of the changes that were brought about post-1945."
Sir Peter Tapsell, the Tory father of the House of Commons, who was first elected in 1959, will attend the sitting to pay his respects but will not be speaking. "It is not a university and I am not the public orator. I don't want it to be thought that I have to get up and make a Periclean speech every time there is a tragedy."
Total recalls
Parliament is being recalled for only the 15th time in 32 years.
The last time was to allow MPs to discuss the riots that swept English cities in August 2011.
Before 2011, Parliament had not been recalled since September 2002, when then Speaker Michael Martin acceded to a request from the government for MPs to debate the situation in Iraq on the day the Downing Street arms dossier was published
In April 2002, MPs returned from their Easter break to express their "deep sympathies and condolences" to the Queen over the death of her mother.
During Thatcher's premiership, the Speaker recalled the Commons on a Saturday to debate the Argentinian invasion of the Falkland islands.
Parliament was again recalled 11 days later, during recess, as Royal Navy ships were "proceeding with all speed" towards the islands, according to then PM Margaret Thatcher.
For MPs to be called back to Parliament the government has to pass a request on to Commons Speaker, who then has the final say.