A campaign group representing millions of women who were caught out when the state pension age was increased has threatened legal action against the government.
Around 3.6million women born in the 1950s were not properly informed of the pension changes which were first introduced in the 90s.
The Women Against State Pension Inequality, known as the Waspi group, has been demanding compensation payments for the millions of women affected.
The government has apologised that its changes were not communicated properly, but told the BBC it "cannot justify paying for a £10.5 billion compensation scheme at the expense of the taxpayer".
Now, Angela Madden, the chair of Waspi, has called the decision "not only an outrage but legally wrong".
A "letter before action" has been sent to the government, a formal step to allow it the opportunity to respond before the group seeks a judicial review at the High Court in two weeks time.
It comes after the parliamentary ombudsman last year recommended payouts of up to £2,950 to each woman affected by a 28-month delay in writing to inform of the changes.