I’m self-employed and eligible for the government’s Covid-19 support package, providing 80% of my income up to £2500/month for 3 months. But my business has grown rapidly, and my income for the most recent tax year is far higher than the 2 before. Will the government calculate my support from an average of the last 3 years income, or just from the most recent tax year?

HMRC will calculate your average profits based on any tax returns you’ve submitted over the last three tax years.

This means that if the average profit over the three year period is under £50,000, you’ll be eligible for the scheme. If the average profit over the three year period is over £50,000, you will be ineligible for the scheme.

If eligible, you’ll get 1 payment to cover the whole length of the scheme, which will be paid in June.

More here: https://www.citizensadvice.org.uk/work/coronavirus-if-youre-self-employed/