Guests and staff were evacuated from a luxury hotel in an upmarket area of central London as 120 firefighters tackled a large fire on the roof.

London Fire Brigade said 20 engines and 120 firefighters and officers had been sent to the scene at the Mandarin Oriental Hyde Park, in Knightsbridge, as huge plumes of thick black smoke could be seen rising into the sky.

Paramedics attended but London Ambulance Service said it had not treated any patients.

Flames could be seen around the top of the hotel, and extended ladders were erected to access that area of the building.

The 12-storey five-star hotel completed the "most extensive restoration in its 115-year history", according to a statement published by owner Mandarin Oriental Hotel Group in May.

All 181 bedrooms and suites are "now more luxurious and comfortable than ever before" and the building's "iconic facade was revitalised", the company said.

The hotel is located between Hyde Park and the Knightsbridge shopping district, which includes Harrods.

A tradesman working at the hotel said he saw a "big fire" on the roof before raising the alarm.

The 19-year-old lift engineer, who gave his name as Harry, said: "I said (to my colleague) 'Lee, there's a fire over there, let's get out of the building. Get out the lift shaft, I'm being serious'.

"We ran down the stairs and went and got the scaffolder out of the loading bay."

One worker, who asked not to be named, said: "The fire alarm started and everybody was told to get outside.

"Everything's fine but we don't know how it started yet."

Eyewitnesses posted videos on social media showing the large column of smoke rising from the top of the building and people in nearby Hyde Park turning their heads towards the sky.

An LFB statement said: "The hotel has been evacuated by hotel staff and crews are currently working to bring the fire under control as well as carrying out a systematic search of the building.

"Firefighters are likely to be on the scene throughout the night.

"The cause of the fire is not known at this stage."