There's currently disruption on First Great Western between Banbury and Oxford due to emergency services dealing with an incident.
All lines are currently blocked and there is no estimate for when a normal service will resume. Also affecting CrossCountry services.
There are also delays of up to 40 minutes on Gatwick Express between Victoria and Gatwick Airport due to signalling problem at Victoria. Some trains may also be cancelled. Also affecting Southern services.
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A further 85 buses are expected to arrive on Tuesday and Wednesday, with officials saying the entire operation will last at least a week.
The government will make an announcement about whether Heathrow or Gatwick should be awarded a new runway at 12.30pm today.
Tuesday morning's weather for the west of the region