Are bailiffs immune from criminal liability?

No

Bailiffs are liable for any criminal offence they commit, but the police may place bailiffs in a class above the law, or say the crime is a civil matter.

If a bailiff recovering an unpaid magistrates court fine, makes an improper charge, he is he shall be liable on summary conviction to a fine not exceeding level 1 on the standard scale.^[1]

If a bailiff who repeatedly charges for work that has not been done, commits fraud.^[2][3]

If the bailiff tampers with the body-worn camera recordings to conceal an offence, he commits an offence of Perverting the Course of Justice.^[4]

If a police officer fails to arrest a bailiff to make gain or detriment to another, and a reasonable person would not expect a police officer to fail to make that arrest, the police officer commits an offence.^[5]

^{[1] Section 78(5) of the Magistrates' Courts Act 1980
[2] Sections 1 to 5 of the Fraud Act 2006
[3] Minister of State, Home Office (Baroness Scotland of Asthal), The House of Lords, 20 April 2007
[4] R v Gary Paul Brown, South London Magistrates’ Court August 2020
[5] Section 26(6) of the Criminal Justice and Courts Act 2015}