UPDATE: The fault has now been fixed and trains are running as normal.

Commuters are being warned that trains could be cancelled, delayed, or changed due to a signalling fault.

The issue, in the Eastleigh area, means trains are running at a reduced speed, according to South Western Railway.

The firm adds that disruption is due to continue until around 4pm this afternoon.

"Your journey is likely to take longer," a Tweet from SWR said.

More to follow.