Almost one in four people aged between 50 and 64 do not know when they will be able to receive the state pension, following recent changes to the scheme.

YouGov polled 1,040 adults nearing retirement on behalf of Age UK and found 24% are in the dark about changes to the state pension.

That's a fair reflection on the UK's biggest state benefit, which has been in a state of constant flux in recent years.

Women have been particularly affected after seeing their state pension age rise to 60 in 2010, and then to 65 on 6 November 2018 to bring it in line with men.

The age at which both genders receive their state pension will rise to 66 in October 2020 and is on course to reach 67 by 2028.

Further increases plan to raise it to 68 between 2044 and 2046 - and the state pension age may rise beyond that. You can understand why confusion reigns.

The state pension: overview

Employers, employees and the self-employed are required to pay national insurance contributions (NICs) on relevant earnings or profits above a set threshold.

The contributions go into the National Insurance Fund, which is where your state pension entitlement comes from.

Class 1 NICs, which are paid by employers and employees, made up 96% of the total contributions to the fund in 2015/16.

You will be eligible for the new state pension if you were born after 6 April 1953 and have at least 10 qualifying years on your NICs record.

You'll need 35 qualifying years of NICs to receive the current maximum amount of £159.55 a week.

If you were born before 6 April 1953, you may be eligible for either the basic or additional state pension, depending on how many years of NICs you have.

Future challenges

90% of the National Insurance Fund's annual outlay in 2018 went solely on the state pension. That's a staggering amount when it's meant to cover other state benefits, too.

The fund is under increasing strain due to the UK's ageing population, and a government review predicts it will be empty by 2032.

There's no pot of money set aside to pay future state pensions, which are funded on a pay-as-you-go basis. That means future pensioners are reliant on the NICs of future workers to pay their pensions.

Put simply, either the fund's income has to rise through an increase to NICs, or expenditure has to be controlled, or the Treasury has to top up the fund by providing a grant.

Restrictions on the level of grant the Treasury can make mean this alone will not be enough to stop the fund from running down by 2032, and the most likely alternative is for NICs to increase.

Increasing national insurance contributions

The longer you work, the longer you continue to pay NICs. This can build the number of qualifying years on your NICs record if you haven't already reached the limit.

It's possible to make class 3 voluntary contributions if you have gaps in your NICs record over the last six years, or class 2 contributions if you're self-employed.

Deferring your state pension can also increase how much you receive when you decide to take it, although this can be a complex decision that requires professional advice.

National insurance credits can plug gaps in your record if you missed paying NICs due to, for example, illness or unemployment.

Check your state pension value

You can check your state pension entitlement at any time.

You will need your Government Gateway user ID and password to login. This will bring up your NICs record relating to each financial year in your working life.

Alternatively, you can request a state pension statement over the phone by calling the Government's future pension hotline on 0345 3000 168.

Talk to us about the state pension.