Pay your HMRC Bill with Curve Fronted and make Hundreds

Assuming you have good credit and are capable of responsibly managing money then the challenging part is: getting £10,000 onto the credit card in the first place, you cannot just transfer money from the credit card without paying cash transaction fees that make the endeavour far less profitable, and any large transactions you might well be able to anticipate are likely to come with costs associated with paying by Credit Card.

Enter Curve Card (link)
a Fintech company that allows you (amongst other things), route payments from credit cards (not Amex!) through Curve and into HMRC tax payments thus avoiding the issue of HMRC not allowing tax to be paid by credit card.

Curve Card is not entirely free. You can choose to either pay 1.5% of the transaction, or £14.99 per month and get the "Curve Black" which you can cancel once the deed is done (there is a £50 downgrade fee). The latter is usually the cheaper option and the Curve Black is easy enough to cancel when it has served your purpose.

A Note on Credit You cannot use an Amex Credit Card which is annoying as Amex are one of the providers that typically offer large Credit Limit. MBNA are normally your next best option - you don't want to go to the effort of signing up for an interest free period to be given a poultry Credit Limit to work with and BarclayCard as a respectable 3rd if necessary.

Stoozing is the borrowing of money from credit cards for free (using interest free periods) and putting the money you borrowed to profitable use until the loan comes due.

For example £10,000 borrowed for 24 months interest free added into a savings account at 5% would generate £1000 over 2 years minus about £60 fees.

Assuming you have good credit and are capable of responsibly managing money then the challenging part is: getting £10,000 onto the credit card in the first place, you cannot just transfer money from the credit card without paying cash transaction fees that make the endeavour far less profitable, and any large transactions you might well be able to anticipate are likely to come with costs associated with paying by Credit Card.