Last month, footage emerged of armed robber Owen Smith dragging PC Ellie Young from a patrol car as he tried to flee a raid on an Esso garage in Horsham.She was left with arm, leg, shoulder and neck injuries after continuing to tackle him alongside colleague PC Vicky Canales.Smith was jailed for 14 years at Hove Crown Court for his part in the raid.PC Anne Bloomfield was left with a fractured skull after being attacked with a Champagne bottle.She had stepped into support a colleague who had been punched and kicked at a property in Nottingham but sustained a hairline fracture of her eye socket, a black eye and bruising to her face and hand. She later admitted she thought she was going to die.Lee Carl Wright was charged with GBH without intent and was jailed for just two years eight months.Another female officer from Nottinghamshire was knocked unconscious by a suspect who hit her with a pair of handcuffs.Chris Bryant, the Labour MP who sponsored the new emergency workers legislation, said the footage of the Merton attack “turned your stomach”.But he warned: “The bill will only be effective if there are enough police officers to implement it and there is the will to act. “We need to have the police, the prosecutors and the courts all lined up and taking it seriously but they also need government backing.”Dave Keen, chairman of the Nottinghamshire Police Federation, said the force was “at a tipping point” and that criminals were becoming aware that back up was further away.“Policing is at risk,” he said. “Every day, officers are going out at fear of being attacked. I would issue a plea to the courts to use these new powers and take it seriously.” Police leaders have warned they will tell officers to let violent suspects go if they do not have broader support following an attack on a female PC.Ken Marsh, chairman of the Metropolitan Police Federation, said if officers were going to get assaulted for simply doing their job, then it was not worth putting themselves at risk.He spoke out after video footage emerged of two officers locked in a violent struggle as they tried to make an arrest in Merton, south London, on Saturday.A female police officer was filmed being kicked in the head during the routine traffic stop, before being left lying dazed in the road clutching her head just feet away from a passing bus.Her male colleague was dragged around in the road as he tried to stop a suspect in a white tracksuit from running away.The female officer had tried to use incapacitant spray on the pair but to no effect.Both were hospitalised following the attack, treated for head injuries and cuts. Martin Payne, 20, from Croydon, was detained and charged with assault under new legislation designed to toughen up sentences for those who attack emergency workers. The other two suspects remain at large.Mr Marsh said: “Are we now in a society where, if we think we can’t detain somebody, we just let them go? It’s just not worth it.”We’re going to come to a point where we’re going to start pushing messages out to our colleagues: ‘Risk-assess it dynamically and, if you think you can’t detain a person, just let them go.'”We don’t come to work to get assaulted, and if we’re not going to be backed up in what we’re doing then what is the point?”He told the Telegraph that their numbers and finances had been “stripped down to the bone”, warning that a police officer in London was attacked every hour.“Society has changed, people think it’s OK to drop kick a police officer in broad daylight because they have impunity – nothing really happens.”He said the new Assaults on Emergency Workers (Offences) Act would only help if it is legislated correctly and the powers are used.The latest attack follows a spate of assaults on female officers. A man was seen jumping and kicking a police officer in the head A member of the public helped the male officer in the struggle but several cars went past without stopping and the person filming the attack did not appear to step in and help. 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.