A 67-year-old convicted double murderer and former Royal Navy serviceman has received a 22-year extended custodial sentence at Winchester Crown Court after being found guilty of thirteen non-recent sexual offences committed against three men and a child.
Allan Michael Grimson, residing at Grove Road in Hollesley, Suffolk, appeared in the dock for sentence on Friday 6 November 2026. Grimson is already serving a mandatory life sentence after being convicted in 2001 for the murders of two young men.
Following an extensive historical inquiry conducted by detectives from Hampshire & Isle of Wight Constabulary, Grimson was formally served with a postal requisition in February 2025. His Crown Court trial opened on 29 June 2026, examining a catalogue of violent and predatory sexual offences committed across a five-year period between 1994 and 1999.
The prosecution outlined that Grimson, who served as a Petty Officer in the Royal Navy, targeted multiple victims across Hampshire and the north east of England. Several of the offences took place at a residential flat situated on London Road in Portsmouth.
On 27 July 2026, the jury returned guilty verdicts across the entirety of the indictment:
One count of rape of an 18-year-old man in Portsmouth (1999)
Four counts of indecent assault of a 14-year-old child in Portsmouth (1999)
Five counts of indecent assault of a 17-year-old boy in Portsmouth (1999)
One count of indecent assault of a 19-year-old man in Tyne and Wear (1994)
One count of indecent assault of a 19-year-old man in Portsmouth (1999)
One count of taking indecent photographs of a child in Portsmouth (1999)
Under the provisions of the Sexual Offences (Amendment) Act 1992, all victims and survivors in these proceedings are protected by mandatory, lifelong statutory anonymity. Any publication, broadcast, or public dissemination of information capable of leading to their identification is strictly prohibited under UK law.
Sentencing Grimson at Winchester Crown Court, the presiding judge handed down a total custodial sentence of 22 years, ordering that he must serve a minimum of 13 years behind bars before becoming eligible to apply for parole release. The sentence took effect from 27 July 2026.
In addition to the custodial term, Grimson was made subject to statutory notification requirements on the Sex Offenders Register for life, alongside comprehensive post-conviction protective orders.
Image – Anonymous Artist Impression
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