Armed robbers dropped off £1 million on a grassy bank following a terrifying hijacking of a Securicor van.

It was then picked up and police believe the robbers may have switched the money to another vehicle.

The cash, which was stolen on Tuesday morning, was left on the bank in Faygate Lane, Horsham, a short way from where the van was abandoned.

When the van stopped to drop off the money, an "oldish" white saloon car pulled up behind it, police said.

The driver of a white Nissan open-backed truck overtook both stationary vehicles and then stopped a short way up the lane.

The drama unfolded between 9am and 9.30am when a man approached the Securicor van, which was parked outside a parade of shops in Fitzalan Road, Roffey, Horsham.

He was described as black, in his 20s, 6ft, well built and wearing a blue Securicor-type open face helmet and dark jacket, with the word Security in white across the back.

The Securicor workers, a man and a woman, were forced at gunpoint to follow a green Rover in the van to Faygate Lane about ten minutes drive away, where the money was dumped and the saloon car and truck were seen.

Detective Inspector Steve Johns, of Horsham CID, said: "I am very keen to speak to the driver of the truck as he may have some significant information."

Both Securicor staff were said to be "extremely shaken" by their ordeal.

The Securicor vehicle is being examined by forensic investigators.

Securicor is offering a £100,000 reward for information leading to the conviction of the gang and the recovery of the money.