Canada's Ben Johnson Thursday slammed critics of Britain's Dwain Chambers, who was banned in 2003 after failing a drugs test, saying the sprinter deserved his place at the London Olympics. Johnson, who was stripped of his 100-meter gold medal at the 1988 Seoul Olympics after testing positive for steroids, said other athletes should look at themselves before casting judgment. “People shouldn't be pointing fingers, they should be worrying if they pass the test,” Johnson told ITV News. “Many people who pointed fingers at me tested positive later on. “He deserves a second chance,” added the former athlete. “There are many people who've done bad things in the world but we don't know.” Chambers was last week cleared for the London Olympics after the British Olympic Association officially rescinded its lifetime ban for athletes found guilty of doping offences. The formality followed the Court of Arbitration for Sport (CAS) ruling which declared the BOA's controversial bye-law to be in direct contravention of the World Anti-Doping Agency (WADA) code. Johnson said he would not be watching the London Games and hit out at British athletes who said Chambers should not be allowed to race. “Who are they to decide whether he competes or not?”, he asked. “You don't see those guys 24/7, what they do in the middle of the night”. Jamaican competitor Asafa Powell also backed London-born Chambers, who is set to compete against world-record holder Usain Bolt in the Czech Republic Friday. “He really deserves this and he's a real cool guy,” Powell told ITV News. Bolt faces multiple threats in London Usain Bolt will find it tough to repeat the sprint double at the London Olympics because there is stiffer competition than four years ago, former 100m champion Linford Christie warned. Bolt, the fastest man on the planet, won the 100m and 200m Olympic titles in Beijing in 2008 in world-record times and then ran even faster in both events at the world championships in Berlin in 2009. Briton Christie, the 1992 Olympic 100m gold medallist, said Bolt remained the favorite to defend his titles, but would face a strong field in London. “Bolt is fast but the competition will be cut-throat this time,” Christie told reporters during a visit to Bangalore to promote a marathon. “There is Tyson Gay, Asafa Powell, Nesta Carter and others. The way Bolt won in 2008...it may not happen that way. Someone, somewhere will come up.” Christie slammed the way Bolt was disqualified from the 100m at last year's world championships in Daegu, South Korea, due to one false start. “It is not good,” he said of the existing rule. “It takes away the explosive starts that are such an important part of sprints. Now the athletes are just waiting back for the starter's pistol to go before they launch from the blocks.”