On October 16, through trains between Mill Hill East and central London, except at peak times and weekends, are to stop.

This is a backward step, just when Transport for London (TfL) should be looking at enhancing and extending Underground lines in order to encourage more people to use public transport instead of their cars, as concern grows about carbon dioxide emissions.

The official excuse for bringing in the Mill Hill shuttle service - that it will improve reliability on the rest of the line - merely highlights how far away the Northern Line still is from operating at its maximum potential.

The new signalling and other work promised on the line over the next few years will do no more than bring services up to the standard they would have been at already if London Underground hadn't been starved of investment for decades.

Now is the time to start discussing what could be done in the next phase once the current upgrade of the Northern Line is complete. Instead of maintaining the status quo at best, or downgrading services, TfL should be looking at new facilities. An idea I would support would be to extend the High Barnet branch to South Mimms, to create a park and ride scheme, enabling motorists from north of London to avoid coming inside the M25 at all.

Andrew Newby, Barnet Green Party