National Rail Enquiries suggests via Havant. It also says you can use "GWR services between Portsmouth Harbour and London Waterloo"?????.....
I'm also amused by the advice to use GWR services via Dorking Deepdene which is closed for engineering works as well.
The whole network is completely stuffed. To anyone stuck I think get to Brighton, then either via Havant or via Hastings and SWR or SE to London.
Also if anyone can get to the Bluebell Railway by bus then there's one more train today at 15:45 from Sheffield Park (121 bus) or at 16:02 from Horsted Keynes (270 bus I think) which gets you to East Grinstead.
270 bus Brighton-Haywards Heath-East Grinstead.
https://www.metrobus.co.uk/services/MB/270?date=2026-06-14&direction=outbound Might help anyone at HH. One more service today.
Another option for anyone in Brighton / Lewes is a number 29 bus to Uckfield (hourly trains to Oxted) or Tunbridge Wells (SE).