The investment platform found that nearly a quarter (23%) of men and almost 40% (39%) of women said they planned to rely on their spouse’s pension in retirement.

But experts warn that this could lead to problems later on, especially if a couple are unmarried. In the event of a break-up, the person without their own pension provision could be left with very little. Even if a couple stays together, surviving on one income could be difficult.

Almost a quarter (24%) of the 18 to 24 age group said they thought they would have to rely on a partner’s pension when they retire, while 43% said they wouldn’t. Older age groups were less confident with 36% of 35 to 44-year-olds saying they thought they would rely on their partner.

London topped the poll with more than half (53%) of people saying they expected to rely on their partner’s pension. This compares to just 23% of people in the North-West.

Helen Morrissey, senior pensions and retirement analyst at Hargreaves Lansdown, said: “Telling a happy couple to consider their finances in the event of a split is hardly romantic but could save a lot of financial heartache in the long run. While it makes sense for couples to share financial responsibilities, leaving long term planning such as a pension primarily in the hands of one partner could leave you financially vulnerable in later life.

“If your partner has a much better pension than you then it is tempting to rely on that rather than build your own, especially if you’re on a lower income. However, if you choose to take this approach, you need to understand the risks you’re taking.

“If you’re not married, then in the event of a split, you won’t be entitled to a share of the pension at all. If you are married, then within a divorce, women tend to leave with less than half of the pension. This is often because women will offset it in an effort to keep the family home, especially if they have primary responsibility for the children. However, this could leave them with a massive hole in their retirement finances.

“Even if you stay together, you need to consider the practicalities of sharing one income, managed by one of you, especially if you have different financial priorities. Often both of the couple will want the security and independence of their own income.”

The figures show women are particularly at risk, with almost 40% saying they expected to rely on a partner’s pension in retirement. This is down to a variety of factors including lower wages, part-time work, and time out of the workforce for caring responsibilities. However, almost a quarter (23%) of men also said they would likely need to rely on a partner’s pension.

Tips to boost your pension

* Increase your pension contributions whenever you can

* Check if your employer will match increased contributions to your workplace pension

* Track down any missing pensions from previous employers