A man who told a police officer to “f*** off” while celebrating the death of Margaret Thatcher could not be sentenced after bungling prosecutors lost his case file.

Armands Strautins, 31, of Mornington Terrace, Mornington Crescent, sat drunk on the steps of St Martin-in-the-Fields in Trafalgar Square and shouted “f***ing pigs” to officers who asked him to move on at about 9.20pm on Saturday.

Strautins admitted being drunk and disorderly in a public place.

He faced sentence at Westminster Magistrates’ Court yesterday, but his file could not be found by prosecutors.

Strautins left the courthouse at 3pm after waiting five hours for his case to be heard.

District Judge Michael Fanning decided to adjourn until May 2 for sentencing.

Strautins first appeared in court on Monday when magistrates heard his offence was in breach of an electronically monitored curfew.

The curfew had been imposed for obstructing a drug search just days before on April 9.

The conditions of the community order for that offence stated that he should be indoors between 8pm and 6am every night.

Strautins had also admitted breaching the community order.

He was just one of hundreds of people who gathered near Nelson’s Column and surrounding areas on Saturday to protest against the former prime minister’s legacy.

In total, 16 people were arrested in connection with minor disorder that broke out at the “death party” demonstration.

They let off party-poppers and chanted slogans about Lady Thatcher who died at the Ritz Hotel on April 8.