Basically started the car up at work as normal and brake warning light came up, fluid was ok and had brakes so assumed it was to do with the parking brake switch and drove off, a while down the road the brakes started to feel proper shit and not working properly and pulled over, turned the car off and the level in the reservior had gone up!! Turned the ignition on too see if letting the abs pump prime would drop it but it made it go even higher, and also rather than cutting off after a minute or so as normal it just carried on priming non-stop?! Decided to disconnect the connector on abs pump and hoped id have some brakes but no silly idea

so pulled over again and re-connected it again.
Moved the car back and forth a bit and the warning light went out so checked the reservior and level was dropping and brakes started working again?!!?! Actually seem a bit sharper now too...............
Any ideas to a cause of this?! Gonna flush all the old fluid out anyway and get some new stuff in ther ebut be good to have an idea as to whats causing it.
Cheers
Tony