There are different ways of measuring how punctual trains are. None of them are good for Southern or their customers at stations like East Croydon, Sutton, Mitcham Junction and Epsom, and London Bridge.

Your Local Guardian:

The company, which is run by the Go Ahead travel group and French private sector firm Keolis, was the worst performing in and out of London, according to this table released today by watchdog group Travelwatch.

If the table - which measures PPM or the percentage of trains that arrived at the station 'on time' but really within five minutes of their scheduled arrival - looks grim, it gets worse.

By another measure - called right time arrivals and measuring the percentage of trains early or within 59 seconds of schedule - only 46.4 per cent of trains were on time in the first three months of the year.

The Travelwatch report says: "A significant proportion of this poor performance can be attributed to, but is not exclusively dependant on, on-going works at London Bridge, with problems compounded by, poor timetable planning and not enough tracks on the approach to London Bridge, numerous points and track circuit failures, and engineering works."

Southern said: "January saw a reduction in the number of tracks into London Bridge as part of the Thameslink programme. The infrastructure proved unable to cope with the amount of trains, leading to sustained delays across the network."

And Network Rail, which runs the railtrack network, said: "We still have challenging days, but these are now far less frequent and we are managing disruption more effectively."

Travelwatch will discuss the full report tomorrow.