It happened on Tuesday evening in Chatham - near Brompton Barracks, headquarters of the 1 Royal School of Military Engineering Regiment.

A woman said she heard a "huge scream", ran to her window and saw the attacker stabbing the soldier on the ground before escaping on a moped.

The army declined to comment on reports the soldier was in uniform at the time.

Sky News understands it's not currently being treated as a terror attack.

Kent Police said the victim is in his 40s and described his condition as serious.

Police were called to the scene around 5.55pm, with the 24-year-old suspect arrested at 6.20pm.

Defence Secretary John Healey called the incident "shocking", adding: "On behalf of the government, I wish him a swift recovery."

The incident comes 11 years after Lee Rigby was murdered near the Royal Artillery Barracks in Woolwich, southeast London.

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An army spokesperson said: "We're very sorry to confirm that a soldier has sustained serious injuries in an attack in Chatham, Kent.

"Our thoughts are with the soldier and their family and we request that their privacy is respected at this difficult time."

They added: "We will continue to work closely with Kent Police to understand what happened and support the investigation.

"Anyone who witnessed the attack or who has any relevant information should contact Kent Police."

Brompton Barracks trains soldiers in construction and engineering skills before their first posting to an operational unit.

It's been the home of the School of Military Engineering since 1812.