There are delays to train services this afternoon (Friday) due to a trespass incident on the railway line at Kintbury.
The National Rail Enquiries service announced: (This) means all lines between these stations are blocked."
As a result, trains may be cancelled, revised, delayed by up to 60 minutes or diverted.
The incident was reported at 2.22pm and affects Great Western Railway services between London Paddington and Exeter St Davids.
It was said to have been over and dealt with delays are possible until 4pm or after.
UPDATE: National Rail Enquiries said trains were running as normal again at 3.50pm.