HGV fleets operating in London may need to be retrofitted with bigger windows in their cab doors if proposals announced this week by mayor Boris Johnson get the green light.

Following the launch of the Safer Lorry Scheme earlier this week, which requires the majority of HGVs to be fitted with sideguards and close-proximity mirrors to help protect vulnerable road users, the mayor said further tightening of the scheme is being explored.

Proposals include the requirement for all HGVs entering the capital to be retrofitted with larger side windows to eliminate blind spots and give the driver better all-round visibility.

The mayor said these can be fitted to the majority of lorries and will cost around £1,000.

A consultation will take place in January on the principle of the proposal and the best way to enforce the new windows, while work will take place with freight operators, cycling groups and vehicle manufacturers to develop a technical “direct vision standard” - necessary to make the windows legally enforceable.

This is expected to be complete by March or April.

In the meantime, the mayor’s office said “as soon as the work can be physically completed”, it will become mandatory for vehicles working on Transport for London, Crossrail or Greater London Authority schemes to be fitted with larger windows.

An additional proposal will also seek to ensure major construction schemes in the capital provide mandatory routes for HGVs to follow to site, which will minimise left turns and remove them from roads heavily used by cyclists.

Discussions with the London Boroughs and the construction industry are already underway.

Finally, existing trials taking place at the Transport Research Laboratory of cycle-protection equipment, such as electronic sensors, may lead to additional mandatory requirements for HGVs if significant and consistent benefits are found.

The existing Safer Lorry Scheme introduced this week, covers every road in Greater London, except motorways, and will operate 24 hours a day, seven days a week. It will be enforced by the police, the DVSA and the joint TfL and DfT-funded Industrial HGV Taskforce (IHTF). The maximum fine for each breach of the ban will be £1,000. Repeat offenders may also be referred to the relevant Traffic Commissioner for investigation.