Robert Haley served in the second world war but has lost thousands because he moved to Australia

There aren’t many people left alive on this planet who can, like London-born Robert Haley, talk about how he joined the Royal Navy at 17 in 1942 and saw almost four years’ active service during the second world war. He was one of thousands of seamen who risked their lives in the Arctic convoys to Russia between 1941 and 1945.

Haley, now 94, earned a lapel full of medals – so why, say campaigners, has the UK government penalised him by freezing his state pension for almost 30 years? That has left him up to £4,200 out of pocket this year alone. All told, he has been deprived of as much as £62,000 since he turned 65 – money that could have transformed his retirement years.

Haley has effectively been “punished” for moving to Australia, a Commonwealth nation, rather than one of the countries where your state pension increases in line with inflation.

He is one of more than 500,000 Britons overseas losing out as a result of the UK’s “frozen pensions” policy. Their basic state pensions don’t increase every year, as in the UK – they are permanently frozen at the date the individual retired or arrived in their country of residence.

Last Monday was Commonwealth Day, and the press release talked about “delivering a common future”. But those words may feel hollow to some: the highest numbers of affected pensioners live in larger Commonwealth countries such as Australia and Canada.

What has angered campaigners even more is that the government recently announced that, post-Brexit, it would continue to annually “uprate” UK state pensions for expats living across the EU, but it can’t or won’t find the money to boost the pensions of Britons living in the “frozen” countries.

Haley was born in Ealing, west London, and spent four-and-a-half years in the Royal Navy between 1942 and 1946. As a result of his service, he has eight British medals and three Russian medals.

But despite that, Haley receives a UK state pension that has been frozen at £46.90 per week. If he had stayed in the UK or moved to one of a list of other countries, he would be receiving a lot more than that. The full UK basic state pension is £129.20 a week, and will next month rise by £5.05 to £134.25.

Haley, who lives in a retirement village in a suburb of Sydney, told Guardian Money that it was “crazy” that the UK was able to get away with paying “paltry” sums to people like him. He, his wife and daughter (who is now 64) went to live in Australia in 1965. He does receive a monthly payment from the Australian Department of Veterans’ Affairs in recognition of his service in Australian waters. But while the department has a “gold card” for its Australian veterans, with most of their health and welfare covered fully, Haley is not entitled to this.

Campaigners say cases like these highlight the unfairness of the UK policy. There are more than 100 countries worldwide where the UK basic state pension is not “uprated” each year. In addition to Australia and Canada, they include South Africa, New Zealand and India.

If you move to one of them, your UK pension will be frozen at the date you retire, or when you arrived, no matter how rich or poor you are, what job you did, or how much national insurance you have paid.

But if you move to an EU country, the US, or one of a seemingly random list of places such as Jamaica and Mauritius, your state pension increases in line with inflation.

The policy has been in place for decades, and ministers have conceded the rules are “illogical”. However, they argue it would be too expensive to uprate those affected, and that the priority should be targeting money at the poorest pensioners at home.

Ministers have previously estimated that to fully uprate everyone’s frozen pensions to current levels would cost more than £500m a year. However, campaigners say that so-called “partial uprating” would involve a much lower upfront cost: £37m.

The all-party parliamentary group on frozen British pensions reformed last month and will be calling on the government to extend the promise made in the EU withdrawal agreement – that UK nationals living in Europe by 31 December 2020 will get their UK state pension uprated every year for as long as they continue to live there – to pensioners living in frozen countries.

The Department for Work and Pensions has previously said that overseas recipients of the basic state pension will only get a yearly increase if they live in the European Economic Area (EEA), Gibraltar or Switzerland, or in a country with a reciprocal agreement with the UK that allows this to happen.

Meanwhile, veterans impacted by this issue will be calling on minister for veterans’ affairs Johnny Mercer MP to support their call for action. The 95-year-old second world war veteran and campaigner Anne Puckridge, who lives in Canada, will also return to the UK this year to continue pressing their case.

Find out more about the campaign at endfrozenpensions.org