<<Events enabling forfeiture. If a member, deferred member or pensioner member is convicted of treason or offence(s) under the Official Secrets Act and is sentenced to at least 10 years imprisonment, or is convicted of an offence that the Secretary of State considers to have been gravely injurious to the defence, security or other interests of the State, or has incurred a monetary obligation to the Crown which arises out of criminal, negligent or fraudulent act and is in connection to service in the Armed Forces, benefits may be forfeit.>>
Scheme rules apply and although the Forfeiture Act of 1870 is largely consigned to history and repealed, section 2 still applies. The police service is particularly hot on pension forfeiture and it was speculated that David Kelly was threatened with disciplinary action that may have resulted in forfeiture.
I have an ongoing FoA request with the MoD about this very thing.
https://www.whatdotheyknow.com/request/afps