This allowance is currently £40,000 a year.
You can contribute up to 100% of your salary towards your pension savings and still get tax relief, as long as the combined contributions from you and your employer are below the annual allowance. This applies to all the pension schemes you belong to.
The annual allowance could reduce if you start taking retirement benefits but also carry on saving into any pension scheme you’re a member of. If you do this, the money purchase annual allowance could apply to you. See What is the money purchase annual allowance for pension contributions?