The idea of the new pension arrangements is to offer a flat-rate pension – expected to be worth around £155 a week – and do away with the other elements that currently make up the state pension, such as the additional state pension and savings credit. The current full state pension provides £113.10 a week.

Fewer qualifying years of National Insurance contributions reduce the weekly amount accordingly.

To qualify for any amount of the new pension in future, you will need to have at least 10 years of qualifying National Insurance (NI) contributions. The current rules require just one year’s payment to be eligible for some state pension payments.

Experts have recommended that expats and former expats seek advice on whether they should make voluntary contributions to plug any gaps in their NI contributions. The decision will depend on personal circumstances and it may be more prudent to put the money into a separate investment.

Dawn Register, partner at BDO Tax Dispute Resolution, said: “Financial advice considerations need to be taken into account as it largely depends on life expectancy and future intentions on where you are going to live. It may be worth checking whether or not you are entitled to a full state pension, and you can check by asking the National Insurance office. Then you can make a decision on whether you want to plug the gap.”

Expats who have moved overseas permanently are not able to get a refund on their NI contributions, even if they have no plans to retire in the UK in the future.

Adam Cole, specialist in advice policy at independent financial adviser Towry said: “The UK’s NI system is ‘pay as you go’ so you cannot get a refund as such. But if you have paid in to qualify for the state pension, then you are entitled to some amount of state pension.

“Certainly within the EU, if you have paid in [to the UK scheme] and met the minimum thresholds you would be able to claim the state pension.”

If you are working abroad, you may still be eligible to pay NI contributions in the UK depending on where you are working, who for, and for how long, added Patrick Connolly, certified financial planner at Chase de Vere.

“If your UK employer sends you abroad to work, for up to two years, you might simply need to carry on paying UK National Insurance as usual,” he explained.

“If you leave the UK you may need to decide whether you wish to pay voluntary National Insurance contributions while you are away. This is likely to depend on whether you plan to claim the UK state pension in the future, whether you’re likely to be returning to the UK and on the state pension entitlements you’ve already built up.

“Either way, you should make sure that you understand the rules which govern your entitlement to the UK state pension.”