Tommy Robinson was among 300 people arrested at the march under public order lawsCredit:Joe Giddens/PA Internal police documents reportedly show that two undercover officers were deployed to spy on anti-fascist campaigners at the demonstration.The covert officers are said to have been arrested along with the activists so they could disappear. Kevin Blowe, the coordinator of the civil liberties group The Network for Police Monitoring, said: “Their role was surveillance on a new and emerging anti-fascist movement – its size, structures, allies and prominent members.”Scotland Yard said: “The Met will neither confirm nor deny the deployment of undercover officers during any specific event or operation. “The covert nature of undercover policing is central to its effectiveness.”An inquiry led by retired judge Sir John Mitting is currently investigating how undercover officers have gathered information on more than 1,000 political groups since 1968. The groups include anti-racist campaigners, environmentalists, left wing groups and the far-right. Scotland Yard has paid out £729,000 in compensation to activists who claimed they were unlawfully detained while marching against the English Defence League (EDL).The campaigners said they were arrested and held for up to 14 hours while they were opposing an EDL demonstration in Whitechapel, East London, on 7 September 2013.Tommy Robinson, who founded the EDL but left the group after the protest in October 2013, was among 300 people arrested at the march under public order laws.The EDL had intended to march to an East London mosque and violent clashes broke out between their members and opposition groups during the protest.Two groups of anti-fascist campaigners were surrounded and detained by police who said they had to take action to “prevent an imminent breach of the peace”.But the force has now agreed to pay 153 activists who claimed they were unlawfully detained an average of £5,000 each in out of court settlements, according to The Guardian.Some of the claimants said they were humiliated and prevented from using the toilet or getting food and water for hours before being taken to police stations and released. The Met confirmed it had settled the claims without admitting liability. A further 28 cases are yet to be resolved. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.