Married Britons could reduce their tax bill by £1,242

“By applying on GOV.UK, rather than through a third party, you get to keep 100 percent of the tax relief due.”

As Ms MacDonald identifies, a direct claim through the Government website is the only way to ensure Britons get all of the money they are due.

Other organisations offer a Marriage Allowance tax claim, however, they are likely to take a cut of the money a person would otherwise receive.

However, if circumstances change, a couple will need to cancel their Marriage Allowance.