The London Underground is set to grind to a halt on Wednesday evening (5 August) as rail bosses and unions failed to strike a deal over conditions. Talks between unions Aslef, RMT, and TSSA and London Underground (LU) are ongoing, but reports suggest that a new offer by LU does not go far enough to appease the unions.

LU is rolling out a new Night Tube service across the capital, which is due to commence from September. And while Underground workers are not against the idea, they want assurances on the number of weekends they would be expected to work.

The strike, which is due to start at 9.30pm on 5 August, would mean commuters would be expected to scramble for other means of transport for most of the day on Thursday. A 48-hour strike in July saw enormous queues forming at train-station platforms and bus stops. Transport for London put on about 200 extra buses, including 1960s Routemasters that were called out of retirement for a strike in 2014.

An Aslef statement read: "The overwhelming view of our members is that this offer is not acceptable. The main concern is the complete lack of firm commitments on work life balance for train drivers. Our members want guarantees on the number of weekend rest days they will have under both the interim and long term arrangements for night tube. Vague phrases like "will seek to mitigate" and "will explore" are simply unconvincing.

"We would be prepared to continue discussions to try to find common ground, but senior management are insistent that new rosters will be issued this week so that Night Tube starts on September 12."

The sensible option, the union added, would be to postpone the launch date to allow for an agreed way forward to be reached.