Thousands of the 3.9 million women who have been forced to wait up to an extra six years to get their pensions are expected to take part in a protest outside parliament.

Women in their 50s and 60s have been hit by the government’s decision to increase the female state pension age from 60 to 66, with some left destitute. Many say that a lack of sufficient information about the rise meant they did not find out about it until they reached 60, leaving them with no time to make alternative plans.

The protesters will march from Hyde Park to Parliament Square on Wednesday, where they will hear from speakers including the Women’s Equality party leader, Sophie Walker.

Women affected by the changes have lost their homes and some have become homeless, with others experiencing extreme stress and hardship. A recent survey by the pressure group BackTo60 found a significant proportion of respondents reported feeling suicidal, attempted to take their own lives or self-harmed.

Helen, 61, from Wakefield in West Yorkshire, began working and paying national insurance at 15. “In April 2016 I decided to find out what my state pension would be in October, with just six months to go. I didn’t know the age had increased. I had been made redundant in early 2013 and thought I could make my redundancy money last until I retired.

I have to go to food banks to put food on the table Colleen, 63

“I sit in my house with no heating on all day, I wear jumpers upon jumpers and cover myself in blankets because to heat my house would be too expensive,” she said. “There isn’t a word bad enough for me to explain what I think of the treatment I’ve received from successive governments.”

Colleen, from Aylsham in Norfolk, said: “I’m 63 years old and I started work at 15. When I got married at 17 and started my new job two days after my wedding. I never received any letter about my state pension age and only found out [about the change] when I signed on for jobseeker’s allowance at 59.

“I’m still on JSA and jumping through hoops at the job centre, facing sanctions if I am late. I have to go to food banks to put food on the table. I do not have my heating on and I sit in the dark to watch TV.”

BackTo60 recently lodged a judicial review claim led by Michael Mansfield QC, seeking to force the government to reverse its decision. The application, Mansfield has said, will argue that the pension policy implemented by successive governments is “a gross injustice and is discriminatory”.

“The impact on the economic, social and mental wellbeing of these women, who rightly enjoyed a perfectly legitimate expectation of satisfactory provision in retirement, has been devastating,” said Mansfield and the law firm Birnberg Peirce in a statement.

“It is deeply ironic that all of this is done in the name of equalisation and equality, when the very means employed to achieve this are themselves discriminatory.”

Jackie Jones, a law professor at the University of the West of England, has argued that the UK is in breach of international treaty obligations. In a paper, she said the actions of the government were discriminatory and “must be removed and full restitution substituted”.

Figures released in response to a parliamentary question last month revealed that the government’s complaints team was dealing with 3,214 complaints from women born in the 1950s regarding changes to their state pensions.

The Commons state pension inequality for women committee has tabled a private member’s bill in an attempt to push the government to review pension arrangements for women who have or will be financially disadvantaged by the changes.

The Labour MP Carolyn Harris, who chairs the committee, said women were “desperate, and in some cases destitute”.

“There’s not a day goes by when I don’t hear from at least one woman. It’s constant,” she said. “They planned their finances; they planned to retire; they had jobs which they couldn’t physically do after a certain age, but they hung on there until they were 60.

“It’s one of the most prolific issues that come into my postbag. Not just from my constituents but from women all over the world, because you have women who live in other countries who are British.”

The campaign group Women Against State Pension Inequality (Waspi), is calling for “fair transitional state pension arrangements”, which they say translates into a “bridging pension” paid from age 60 until state pension age.

Their campaign is supported by the Equality and Human Rights Commission, which has said it will raise the issue at the UN, as well as the Fawcett Society.

In 2015, the work and pensions select committee concluded that “more could and should have been done” to communicate the changes. The committee called on the government to explore the option of permitting a defined group of women who have been affected by state pension age changes to take early retirement, from a specified age, on an “actuarially neutral basis”.

The issue has been debated in parliament on a number of occasions. Last November, the Commons voted by 288 votes to none to approve an Scottish National party motion calling on the government to improve transitional arrangements for the women.

But the government has refused to concede to demands for restitution. Last November, Richard Harrington, a former parliamentary under-secretary at the Department for Work and Pensions (DWP), said the government would “make no further changes to the pension age or pay financial redress in lieu of a pension”.

The pensions minister, Guy Opperman, recently denied the DWP had failed to provide adequate and timely information relating to the increase in the state pension age.