The letter by which Boris Johnson resigned as Foreign Secretary was pored over and dissected by political analysts and journalists, but for cycling campaigners there was one passage that jumped it, with the former Mayor of London claiming that EU rules prevented him from introducing safer lorries to the city’s streets.

As we mentioned on our live blog this morning, it was a claim that was swiftly debunked on Twitter, with Mark Treasure, chair of the Cycling Embassy of Great Britain, highlighting that when Johnson was at City Hall, it was the British government he blamed for not implementing EU rules on HGVs.

Here is what Johnson said in his letter to Prime Minister Theresa May yesterday:

It now seems that the opening bid of our negotiations involves accepting that we are not actually going to be able to make our own laws. Indeed we seem to have gone backwards since the last Chequers meeting in February, when I described my frustrations, as Mayor of London, in trying to protect cyclists from juggernauts. We had wanted to lower the cabin windows to improve visibility; and even though such designs were already on the market, and even though there had been a horrific spate of deaths, mainly of female cyclists, we were told that we had to wait for the EU to legislate on the matter.

But that’s not the stance he took as Mayor of London in 2014, when the BBC reported that he was “deeply concerned” at the UK government’s refusal to back EU proposals to improve the safety of lorries, including larger windscreens and windows to eliminate blind spots.

He said: “This is a once-in-a-decade opportunity for the EU to remove some of the blockages which prevent us from making lorries safer in our cities.

“If these amendments, supported by dozens of cities across Europe, can succeed, we can save literally hundreds of lives across the EU in years to come. I am deeply concerned at the position of the British government and urge them to embrace this vital issue.”

A spokesman for the Department for Transport said in response: “We share the mayor’s concerns about the potential benefits of improved cab design and we want to see changes in the industry.

“Where we are not supporting European Parliament proposals, it is simply because they will not produce practical changes in cab design and could lead to additional bureaucracy for Britain.”

Later that year, a “trialogue” session involving members of the European Commission, European Parliament and European Council approved plans for regulations for safer lorries which are due to come into effect in 2019, overcoming opposition from France, home to truck maker Renault, and Sweden, where Scania and Volvo are based.

Ahead of that session, Johnson had joined British Cycling policy advisor Chris Boardman and Kate Cairns, founder of the safety campaign See Me Save Me, in urging the UK government to implement the changes without delay.

In 2015, the Freight Transport Association called on former Prime Minister David  Cameron to ensure the UK government provided incentives for haulage firms to adopt safer lorries.

Despite the forthcoming EU rules which place the onus on truck manufacturers to comply with safety rules, some such as Mercedes have already taken matters into their own hands and are producing lorries with features such as ‘direct vision’ cabs, which are now being picked up by fleet operators in the UK.

Back in 2014, Cycling UK highlighted to Johnson that under existing rules, it would have been possible to introduce safer lorries to London.

Today, the charity’s policy director, Roger Gefffen, told road.cc: “Cycling UK shared Boris’s frustration four years ago when two EU member states blocked efforts to introduce EU-wide rules to require safe lorry cab designs that could save pedestrians’ and cyclists’ lives.

“However we then pointed out a way that safe lorry cabs could be required within the current rules for all but the longest lorries.

“With the current London mayor now acting on our proposals, we hope the UK government will do likewise.

“If the drivers of construction vehicles and refuse lorries could see what’s around them as easily as bus drivers can, our streets would be a lot safer for everyone.”