London Underground has warned that there will be fewer trains on the Metropolitan line next week, while a new signalling system is introduced.

The new signally system is part of a 4-lines upgrade affecting the sub-surface lines (Circle, District, Metropolitan and Hammersmith & City) and is being introduced in phases.

Over the weekend, the new signals between Finchley Road and Euston Square will be switched on. Ironically as the main reason for the upgrade is to be able to run more trains, in the initial bedding in stage, for a week, there will be fewer trains.

The period affected will be Monday 2nd Sept to Thursday 5th September.

London Underground is warning that trains will be busier than usual and, on some journeys, you may need to change trains to complete your journey towards central London.

The project will eventually see an increase in train frequency from 28 to 32 trains per hour in the central London section.

What is known as the Four Lines Modernisation project will finish in 2023, when all four lines are operating completely under the new Thales system. Services will begin to increase in frequency from 2021, when the central London section of the network has been modernised.

The upgrade also means that today (Friday) will be the last day that the venerable old signal box at Edgware Road will be in operation. It will be saved and preserved though, and hopefully opened up in the future for visits.