Eurostar (the train through the Channel Tunnel from London to Paris and Brussels and extensions) train Guards will strike this weekend and over the Bank Holiday weekend.
The strike will be from one minute after midnight on the 12th of August until one minute to midnight on 15 August, and for three days over the UK Bank Holiday weekend from the 27th of August.
If I get updates I'll post them here.
There will be pointers on the France and Belgium Forums.
UPDATE
below