If you can be calm enough to allow it, breathing helps in the short term. A rhythm that makes the out breath longer than the inbreath, eg 5, in 7 out or I discovered 4 in, hold for 7, out for 8.
Or a walk in the fresh air, or something physical as others have said.
It does depend what is driving your anger. We are an unequal, unhappy, anxious, divided country in the wake of the pandemic with scarce resources especially health and mental health services.
There's a company called Benenden who run something called a health plan from £11 a month. It gives you access to private referrals but it also offers 24 hour free counselling for an hour. I've only used the latter a couple of times but it was very helpful.