Martin Lewis' MSE issues advice to pensioners who missed up to £50,000 top-up

's Money Saving Expert has issued some advice to people who missed the deadline to apply for a State Pension top up - which for some could have represented a boost to their pot of up to £50,000. The publication reports that thousands of people were wrongly denied requests to check and top up their State Pension ahead of the crucial April 5 cut off date.

Last Saturday at a minute before midnight was the final opportunity to start the procedure to check and fill any gaps in your National Insurance record between 2006 and 2018. This was offered under transitional arrangements introduced when the new State Pension began in 2016. Most people aged under 73 had till April 5 to add to their State Pension pots by buying any missing NI years.

Usually, it is only possible to pay to top up for the previous six years on your NI record, according to Rosie Hamilton, MSE's Senior Money Writer.

Checking before the April 5 deadline could add thousands, tens of thousands or possibly more to your current or future State Pension.

HMRC has told that the online service, which allowed you to make payments for the tax years 2006-07 to 2020-21, was taken offline by mistake a day before it should have been.

The error meant those who went to check their State Pension forecast on April 5 instead were faced with a message saying the deadline had passed.

HMRC said it will contact anyone affected by the mistake, removing the need to get in touch with them. The problem hasn't affected the DWP's call-back request form, which is separate from HMRC's online service.

An HMRC spokesperson said: "We're sorry that customers were unable to use our online service on Saturday to top up National Insurance contributions for years prior to 2021. We will contact anyone affected directly about the payments they wanted to make to ensure they don't miss out."

Ms Hamilton wrote: "[I]t's worth hanging onto any proof you took of the problems, such as screenshots. And if you don't hear anything, you can try to contact HMRC yourself via its various NI channels."

People who don't have the full 35 years of NI contributions or credits get a State Pension at a pro-rata amount.

Buying a missing year costs between £800 to £900 and if you live a long time, it could be worth thousands of pounds.

While those affected by HMRC's error should be contacted, for anyone else who missed the deadline you will only be able to fill any NI gaps for the last six years.