UPDATE: 1.16pm

UPDATE: 1.08pm

Services are still being delayed by the ongoing repair work to the cables at Filton Abbey Wood.

According to GWR's website, disruption is expected to last until 1.30pm. Commuters from south Wales are being advised to travel via Swindon.

UPDATE: 10.19am

Travellers advised not use this route:

UPDATE: 9.58am

UPDATE: 9.40am

Passengers who wish to defer their journey may use tickets dated today for travel tomorrow, Tuesday 9 January.

There is very limited road transport running between Bristol Parkway and Bristol Temple Meads.

UPDATE: 7.50am

Disruption is expected until 10.00am:

UPDATE: 6.55am

MANY trains through Gwent have been cancelled this morning due to cable theft. 

All services to Bristol Temple Meads have been cancelled and the disruption is reported to be set to last for the whole day.

More to follow.