Despite fine words from high-ranking police officers, an unpleasant incident in Romford last week suggests that officers on the ground are no nearer understanding or respecting photographers’ rights.

This comes just a day after the Met shelled out a large wad of cash to two professional photographers for almost identical mistakes made by officers, exciting speculation that the best rates paid for photographs nowadays are those paid out of the public purse for pics the police disapprove of.

Young photographer Jules Mattsson, 16, was out in Romford at the weekend intending to take photos of a cadet unit who, he blogs, were "about to march in a massive parade". A YouTube clip, containing still images and a soundtrack, allegedly documents what happened when local police officers decided they did not like this idea.

According to Jules, after he attempted to take his first shot, he was "quickly and aggressively stopped by one of their adult officers asking me who I worked for". He refused to provide his personal details – and from there on, events moved swiftly downhill. In the clip, a male officer with an outwardly poor grasp of the law can be clearly heard.

The entire gamut of inconsistent excuses are given for why Jules cannot take photos, ranging from the "fact” that it is illegal to photograph children without parental permission, through to breach of copyright and anti-social behaviour. When all that failed to move the young snapper, the police officer informed him that he was an "agitator" and a "threat under the terrorism act" for photographing a police officer – before removing his camera and frogmarching him away from witnesses and – Jules claimed - pushing him down some stairs.

We asked the Met for comment and were told: "Although at this time we have not received a complaint about this incident and no allegations of crime have been made, we will investigate the circumstances."

There followed a list of the guidelines supposedly issued to officers, which wax lyrical about "promoting the freedom of the public and the media to take and publish photographs". They also state very clearly: "Members of the public and the media do not need a permit to film or photograph in public places and police have no power to stop them filming or photographing incidents or police personnel."

They add: "It would ordinarily be unlawful to use section 58A [of the Terrorism Act 2000] to arrest people photographing police officers in the course of normal policing activities".

Given that such good guidelines exist – and senior police officers regularly provide stern warnings about over-stepping the mark in this area, the Romford incident must surely be just an aberration.

We therefore phoned the Met’s call centre last night to inquire what the law was in relation to taking photographs on the street. The member of staff who took the call was aware that it was legal to photograph police officers – but rather less good when it comes to exercising one’s legal right to photograph other people, including children. He told us: "You can’t just go round taking photos."

Worryingly, he added, in respect of photographing children: "You can understand what is going to happen."

When asked why the police would not protect a photographer going about their lawful business, the call was terminated.

We then asked the Met officially if they could explain this gulf between official guidelines – and the state of knowledge of police officers and other members of the police service who have contact with the public. They have promised to get back to us.

In the meantime, this ignorance of the law is beginning to prove costly for the police. Comedian Mark Thomas set the standard earlier this year when his complaint about police officers stopping him unlawfully – in his case, without a camera – led to a pay-out of £1,200 by the Met. Since the incident in 2007, Mark has encouraged members of the public to bite back, any time they feel the Police have abused their rights.

Meanwhile, photojournalists Marc Vallee and Jason Parkinson last week received compensation of £3,500 apiece in respect of an incident outside the Greek Embassy in December 2008.

Marc told us: "This is the second time I’ve been forced to take legal action against the Metropolitan Police since 2006 and I would like it to be the last. The question to consider is, is the overall harassment of photographers by the police a deliberate policy or a series of unrelated mistakes?

"You have to ask yourself is it in the DNA of Metropolitan Police to restrict and harass photographers? And if so what are we going to do about it?"

The bill for the Met may be about to get a little bit higher, as Marc also informed us this morning that he has just "sorted a lawyer out for Jules". ®