David Davis is Secretary of State for Exiting the European Union in the UK government

Reportedly has resigned.

Twitter sources at this stage only , so treat is as unconfirmed

I'll try for confirmation

Press Association also now "Brexit Secretary David Davis has resigned from the Government, the Press Association understands"

Yep …. wider sources onto it now

GBP dropping away

ForexLive well ahead of the pack on this and on so many other FX-breaking (in this case breaking the GBP!) items