This bus is believed to have been evacuated near Twickenham’s Marble Hill Park last Thursday, the latest in a string of incidents involving London buses smoking or catching fire.

A witness said the bus was a 490 on the way to Heathrow Airport. Operators Abellio initially denied any knowledge of the incident after checking their records.

But today shortly before 2pm they said: "Last Thursday at about 10pm there was a water leak and steam created as a result of a burst pipe on a route 490 vehicle.

From last week: Bus driver accuses Abellio of 'shocking maintenance' practice after two bus fires in same week

"There was no smoke, flames or fire related to this incident. This was reported according to our normal company procedures. “

The passenger, who asked not to be named, had said: "I was just sitting there [on the] second to back seat when I smell smoke and see a woman behind me and another lady staring at her.

"So I think she's dead or on fire, then I notice flames are burning through the seat on the back corner behind me.

"The lady was fine. Within about three seconds the whole bus was filled with smoke and we were all standing outside watching in shock".

From last week: Bus catches fire in Mitcham - moments after school children get off

From last week: Bus explosion: 157 bus evacuated after fire breaks out 

Were you on the bus? Call the news desk on 020 8722 6326 or email george.odling@london.newsquest.co.uk.