Should the London Underground be considered an "essential service" which would ban all future worker strikes?

An “essential service” classification prevents employees of a government service from staging full-scale strikes and walkouts. Services with the classification are required by law to provide minimum services during periods of industrial action. Proponents of the proposal argue that strikes by underground workers cause significant disruption to the country’s economy and people’s lives. Opponents argue that the proposal would prevent workers from exercising their rights.