Weather-related, it must be clarified
Direct quote from
GWR▸ "We had a reduced timetable in place due to engineering work and crew shortages and severe weather has affected the remaining services I am afraid" - so a bit of everything.
They are also telling their customers that they won't be rearranging replacement transport but if you can arrange your own they will reimburse, and whilst not being quite so explicit, suggesting that hotel bills will be met for those stranded. Apparently Paddington is predictably appalling.
What arrangements will be made for any vulnerable customers, or those who don't have the means to make upfront payments, God knows.