Hundreds of passengers were delayed after trains struck a pushchair and a bicycle thrown onto the tracks.

More than 20 trains were delayed and four cancelled last night as a result of the late-night vandalism in Gravesend - with two trains held for several hours while the debris was removed.

The total delay to trains affected by the incident was more than 1,100 minutes, or just over 18 hours.

Both objects were suspected to have been thrown from Stanbrook Road footbridge.

Network Rail South East route crime manager Alice Morton said: “These two incidents happened within hours of each other and left passengers sitting on the trains for some time while the objects were removed and the trains checked for damage.

“Both incidents could have been much more serious, and it’s sheer luck that nobody was hurt. Mindless vandalism like this costs us money that could be spent on making services better and leaves passengers rightly upset about delays and disruption to their journeys.

“I would appeal to anyone who thinks this sort of stunt is funny to think again.

“Anyone who has information on either incident should contact the British Transport Police.”

A Southeastern spokesman said: “It is clearly unacceptable and potentially dangerous to throw items onto a railway track and we can’t stress enough how this causes unnecessary delay to our passengers.

"We urge anyone who has information about either incident to contact the BTP.”

The first incident involving an empty pushchair happened at 9.43pm and involved the 8.20pm Ramsgate to St Pancras International train. The pushchair was removed and trains were running again soon after 11pm.

Forty-five minutes after the first incident, the 9.29pm Faversham to St Pancras International – which was already delayed as a result – hit a bicycle in the same spot.

The bicycle was jammed under the train and the power had to be turned off to allow it to be removed.

Services were on the move again at 12.42am, and the Faversham to St Pancras train reached its destination 157 minutes late.

Anyone with any information is asked to contact British Transport Police by sending a text to 61016 or calling 0800 40 50 40 quoting reference 459 05/06/2016.

Alternatively, information can be passed anonymously to independent charity Crimestoppers on 0800 555 111.