The BBC's Newsnight reported Rob Lewis had created a group chat with other former Met officers.
Some of the posts seen by the programme feature jokes about the government’s Rwanda deportation policy and the recent flooding in Pakistan, which left almost 1,700 people dead.
The programme said it was shown messages from the group by Dave Eden, another former police officer.
“There are references to black politicians, which are extremely unpleasant,” he told the BBC. “The entire undertone is one of racism and misogyny.”
He said: “This group tells me that the culture of the Metropolitan Police hasn’t changed. And in fairness, it’s not just this group, it’s other groups. It’s what I’m hearing out of the mouths of ex-colleagues. And what I’m witnessing all the time.”
In a statement carried by the BBC, the Home Office said it had suspended a member of staff.
“We expect the highest standards of our staff and have a zero tolerance approach to anyone displaying racist, homophobic, misogynist or discriminatory behaviour,” the statement said.
“Where we are made aware of such behaviour we will not hesitate to take decisive action.”
Commander Jon Savell, who is responsible for the Metropolitan Police’s professional standards, said the messages shared were “abhorrent”.
“These messages are abhorrent and have absolutely no place in policing or society,” he said.
“Their behaviour erodes the confidence that the public has in the police – a confidence that the vast majority of us in the Met works tirelessly day-in, day-out to maintain and improve.
“Racism, misogyny, homophobia or any other discriminatory behaviour has no place in the Met.
“Where such behaviour is identified it will be dealt with robustly, but we will also be actively seeking out those whose actions bring shame to us.
“We contacted Mr Eden’s representatives when these messages first emerged in April but they declined to share further details. We urge them to reconsider so we can take action.
“In the meantime we appeal to anyone who has information about such behaviour to make contact.”
Commissioner Sir Mark Rowley added: “My plan for reform in the Met is already under way. I will be ruthless in rooting out those corrupting officers and staff, including racists and misogynists, from our organisation.
“I have taken over as the leader of an organisation that has been far too weak in taking on those who undermine the honest and dedicated majority who determinedly serve the public.
“That will change and I will continue to seek out those, from both within and outside the Met, with that constructive anger who can help us reform.”