No, but there are limits on how much tax relief you can get. You can pay 100% of your yearly income into your pension if you earn £40,000 or under per year; where your salary is the maximum you’re allowed to contribute into your pension a year. For example, if you earned £30,000 a year, you can only pay £30,000 into your pension, and receive tax top-ups.
However, if your income is above £40,000, then £40,000 is the maximum amount you’re allowed to contribute into your pension a year that receives tax top-ups. If you pay any more than £40,000 into your pension, you will stop getting tax top-ups from the government.
Therefore, whatever you earn a month you can put into your account on a monthly basis, but this cannot accumulate to an amount that exceeds £40,000 by the end of the year, including the government’s tax top ups.