An Algerian thief has been jailed for 28 months after trying to grab a £250,000 Richard Mille watch from a Chinese tourist in the heart of London. Brahim Keddad, 29, came up behind Sun Tao and grabbed him on the shoulder before trying to wrestle the timepiece from his victim's wrist.Southwark Crown Court heard Mr Tao, a Chinese visitor to the UK capital, was shoved and fell to the ground - suffering injuries to his knee and arm.Keddad, who has more than 20 past convictions for theft and robbery offences, turned to flee but was captured by a plain clothes Metropolitan Police officer who had been tailing him before the attempted robbery.The defendant, a French national, was sentenced on Friday to 28 months in prison after he pleaded guilty to attempted robbery.Judge Nicholas Ainley said Mr Tao 'must have been terrified by the suddenness of what happened to him, and the force used on him'. And he paid tribute to the plain clothes police officers who were patrolling Mayfair on the day of the incident, April 30.The judge told Keddad: 'I salute their skill in spotting you at an early stage. Brahim Keddad (pictured), 29, came up behind Sun Tao and grabbed him on the shoulder before trying to wrestle a £250,000 watch from his wrist Keddad has now been jailed for 28 months for the attempted watch robbery - the Metropolitan Police released this picture of the £250,000 Richard Mille timepiece targetedIt's plain from what happened that you were on a mission to rob and saw a target in Mr Tao.' He said the actions of the officer who intervened 'might well have meant this offence was not completed'. The court heard Mr Tao was walking from Bury Street to Ryder Street, in the St James's area of London, when he was grabbed from behind by Keddad, at about 3.30pm.Prosecutor Luke Staton said: 'The defendant grabbed Mr Tao's shoulder with both hands and went to grab Mr Tao's left hand, because on his left hand was a Richard Mille watch with an estimated value of £250,000.'The defendant shouted words to the effect of, 'Watch, give me your watch', and he then pushed Mr Tao and had his hands on top of Mr Tao's wrist, trying to remove the watch.'Such was the level of force used that Mr Tao stumbled forward and fell onto the floor, scraping his knee and left elbow in the process. 'At some stage, Mr Tao managed to get to his feet, break free from the defendant and run away.'The prosecutor told how this was 'fortunately' spotted by a plain clothes police officer, who announced he was a police officer and detained the suspect.The court heard Mr Tao was left 'anxious' after the incident, feeling 'not so safe any more to walk around on his own'. The prosecutor added: 'He now feels if he goes out, he is afraid he will get robbed again.'It also made him feel aware of not having a valuable item on him while walking in London.'Scotland Yard said plain clothes officers had spotted Keddad 'acting suspiciously' before the robbery attempt, noticing he was walking slowly and looking at passers-by.One of the officers, Det Sgt Andy Swindells, started to tail him, and chased after Keddad when he took a Lime bike down the road and pounced on Mr Tao.DS Swindells said: 'This case highlights the invaluable benefit of plain-clothed officers being on patrol.'We were able to spot and arrest Keddad within minutes, returning the valuable watch to its owner and preventing others who live or visit in London from being victims.'The Metropolitan Police said rates of theft and robbery have dropped by 14 per cent in the capital in the past year.After being arrested, Keddad said 'I'm sorry', claimed he had not hurt Mr Tao, and added: 'I did it for my daughter.'The court heard he sends money back to France to his ex-wife and young daughter.Keddad, who was living in Islington, north London, was previously convicted in January of an attempted theft from a rucksack at King's Cross station - receiving a six-month community order.He has two convictions for robbery in Spain and a further 19 convictions in Spain mostly for theft offences, the court heard.He is also wanted in Belgium where he was sentenced in his absence last year to three years in prison for theft and forgery.His barrister Elizabeth Garcia said Keddad turned to crime to pay off gambling debts.Keddad was told he must serve half his 28-month sentence and it is understood he is also facing deportation from the UK. Ms Garcia said: 'He owes money to other people due to gambling debts - that is primarily his reason for committing this offence.'As someone who came to this country was effectively homeless, he was staying with a friend but did not have any fixed abode.'As is clear when he said to the police officer, he does have a wife and child in France - an ex-wife, they are separated - but he tries to support their young daughter by sending money and food home.'He has reached a point in his life where he cannot continue to keep committing these offences. He understands these sentences will get longer and longer.'Judge Nicholas Ainley rejected Ms Garcia's characterisation of the robbery attempt as an 'opportunistic crime'.Passing sentencing, the judge said: 'I think that would be a difficult submission to maintain - he's on the lookout for high-value items and he knows where to seize them.'It is plain from what happened he was on a mission to steal and rob and he saw a target from Mr Sun Tao.'He obviously recognised from what he saw a very high value item.'