LONDON Underground could come to a halt on Friday 12 October and the following Friday. Results were due this week in ballots by both RMT and ASLEF union members in a dispute over pay.
Both unions have rejected an offer of 4 percent. Strikes involving all staff are expected to start in mid-October. In a separate dispute drivers on most lines have voted to take action in a dispute over having to begin and end duties in outlying stations.
From Wednesday drivers will be refusing to start or finish work away from their home depots.
Two strike days have already been named for Friday 12 and 19 October. The unions plan to call action on these days in the event of any victimisation by management of members involved in the dispute.