Calm Larry the Cat at No 10 Downing Street had been neutered just before selection for his role

It has been suggested that the celebrity Downing Street cat, Larry, who has kept five Prime Minister's company at the offices and removed all signs of mice from the building, was selected because he was very calm at the time when he was chosen at Battersea Dogs & Cats Home and the reason why he was calm was because he had been neutered the day before.

Government Chief Mouser Larry the Cat questioned over Partygate. Screenshot.

The suggestion is that just by chance Larry and thanks to castration he was selected from a group of five.

I find this implausible to be honest. Although we know that the neutering of male cats makes them calmer. In fact, I did some work on how castration of men changes their character.

I wanted to get into the heads of neutered male cats and tried to do this by researching how the operation affects humans. It might interest you. It's certainly chills out men and that's why male cats become calmer and more manageable.

Effects of Castrating a Cat (and a man)

And it is this character trait which convinced David, who was an Australian staff member at Battersea at the time. He was chosen to choose the best cat for No 10 Downing Street.

He visited Battersea on January 29. He saw five cats, Larry (the successful one), Spencer, Crockett, Trixie and Bart. Larry was chosen "for having the perfect personality". He was less needy than the other cats. This indicated to David that he would be able to cope with the activities at 10 Downing Street as it is full of 400 people occupying 100 rooms.

Number 10 Downing Street is a bit like a Tardis. It looks quite compact from the outside but when you're inside it is a complicated network of corridors and rooms. I have been there.

The Times newspaper tracked down the other cats, the ones that didn't make it to No 10. Spencer is still alive. That's worth stating because Larry looks quite old now. He was adopted in January 2011 to be the working cat of No 10.

Spencer's owners, said: "I don't think Downing Street would have agreed with him". They mean that Spencer would not have got along very well at the Prime Minister's offices.

Realistically, I don't think many cats would. It's just too active. Too much most noise, kerfuffle and commotion to be ideal for a domestic cat.

Crockett apparently would have been a decent mouser. He was rehomed in Forest Hill, south-east London. He died at the age of eight or nine.

Bart could not be traced. Trixie spent her life in Hackney, East London and at a family home in Hampshire before she was euthanised due to ill health in 2015.

Trixie was owned by Charlie, a retired administrative worker. He said that Trixie was a loving cat but shy. She might have found life difficult at No 10 Downing Street.

As for Larry's mousing skills, they appear to have waned somewhat because of his advancing age. But they said: "Having said this, no mice have been spotted in Downing Street for years."