Drivers with Southern and Gatwick Express have voted by more than 4-1 to strike in a bitter dispute over driver-only trains.

The Aslef union said its members at the two rail companies backed walkouts by 84% and other forms of action by 95%. The turnout was 82%.

General secretary Mick Whelan said he welcomed the "strong mandate" from drivers.

The company expressed disappointment at the ballot result and confirmed it was pressing ahead with seeking an injunction against any industrial action.

Govia Thameslink, which runs the two franchises, said: "We are disappointed with the result and will now await notification from Aslef as to what its plans may be. Any action would only heap more disruption on our passengers - passengers who have already been through two recent strikes by RMT union conductors.

"We have repeatedly tried to engage with Aslef on this but the union has refused to engage in any sort of meaningful dialogue. We urge them once more to sit down and talk to us.

"In the meantime, we have sought an injunction from the High Court against any industrial action that may result from this ballot. Aslef selected which drivers it balloted in a way that breaches the strict rules on balloting, and because it induced drivers to refuse to drive trains in advance of conducting the ballot, it cannot now lawfully ask them to take industrial action.

"We expect to hear the result of our injunction application in the next few days."

The company said the case will be heard on Tuesday.

The Rail, Maritime and Transport union later announced that its train driver members at Southern and Gatwick Express have also voted for strike action and action short of a strike in the same dispute.

The RMT is embroiled in a row with Southern over the role of conductors, which has led to strike action in recent weeks.

Unions are also protesting against Govia's plans to close over 80 ticket offices across its franchises.