UK It is illegal to force medical treatment onto someone.

Yes. Not only illegal but unlawful and also a breach of human rights.

The reason the government has not made it statute law and instead chosen to issue it as a "guideline" is because they cannot then be held responsible. Instead the person who is enforcing a guideline is responsible.

If you are being forced to take a test either decline consent or request condition of proof that the test is 1) needed, 2) accurate.

Also you have an unalienable natural right to travel under law. Statute legislation is contract law and requires your consent. Tell them you are traveling and state you DO NOT CONSENT and that they are acting unlawfully by inhibiting your travel and are personally responsible

Thanks, I am trying to clarify if the corona test is technically classified as a medical treatment? Then it would be illegal under uk law to pressurize you into taking the test at airports and sea ports.

Found this if anyone is interested, it is a deciding factor in taking the test and it's legality in England and to leave England I suppose,

Relating to the 2019/2020 changes to the act,

The of the Public Health (Control of Disease) Act 1984 makes explicitly clear that the power to make such regulations does not include mandatory treatment or vaccination.

45E Medical treatment

Regulations under section 45B or 45C may not include provision requiring a person to undergo medical treatment.
“Medical treatment” includes vaccination and other prophylactic treatment.

Has the Coronavirus Act 2020 changed this?

No.

Powers to make regulations in England and Wales are made under and subject to the restrictions in the 1984 Act.