Photo for illustrative purposes only Image Credit: Getty Images

For the Twitter feed of London's Metropolitan Police, Friday seemed like an ordinary day.

It announced some arrests. (Teenagers obstructing a road at a protest.) A man was jailed in a murder case (life, for killing a "friendly pensioner").

Then things started to go sideways.

For about 40 minutes, the account spewed messages, some irreverent, others incomprehensible, that suggested perhaps the police were no longer in charge.

"XEON IS THE BEST FIGHTER IN SCOTLND," one message read, without elaborating.

Soon the account started hurling expletive-laden messages denigrating police officers, making it clear that the account had been compromised. The posts would appear, then a few minutes later would be deleted, suggesting that some sort of cyber tug-of-war was under  way.

Another message read, "no comment get my lawyer."

"FREE DA GANG!! #CHUCKLINGHELLA," one post read, including an obscenity directed at police officers.

In an email late Friday, the Metropolitan Police confirmed that it was facing "security issues," but said they were relegated to an online service used by the agency's press bureau. The agency said there was no broader hack of the Police Department's servers.

The press bureau's online service is used to issue news releases and other messaging. When things are posted using the service, the messages go on the agency's website and its Twitter account, and an email with the message also goes out to subscribers. All were affected during Friday's antics.

"We apologise to our subscribers and followers for the messages they have received," the Metropolitan Police said in the statement.

It said the police did not know who is responsible or what exactly happened but noted that an investigation was under way.

"We are assessing to establish what criminal offences have been committed," the police said.

The Metropolitan Police is far from the only organisation that has temporarily lost control of its social media messaging.

In 2017, several of television channel HBO's Twitter accounts were hacked. Hackers wrote in Twitter "we are just testing your security" and "let's make #HBOHacked trending!"

Also that year, McDonald's said its Twitter feed was briefly compromised. One tweet read: "@realDonaldTrump you are actually a disgusting excuse of a President and we would love to have @BarackObama back, also you have tiny hands."

Still, Friday's mischief, directed at a police force, offered some particular irony, as one message posted by the miscreants read, "what you gonna do phone the police?"