This live event has finished
- The M40 is currently closed at Junction 4 as police attend a man on the wrong side of the barrier at the bridge by Cressex Road.
- There are long delays between J2 A355 (Beaconsfield) and J4 A404 / A4010 Handy Cross, as the M40 is closed in both directions.
- The incident is causing gridlock on the roads around High Wycombe and Marlow.
The BFP is concluding its live blog on this incident - but we will bring you an update as and when we receive further information from Thames Valley Police.
Police have just confirmed the incident is still ongoing.
Traffic Link estimating current travel time on the M40 is one hour and 20 minutes, with roads around Wycombe congested as motorists are leaving the motorway and travelling through the town.
All emergency services and the Highways Agency are currently at the scene, working to resolve the situation.
It is reported roads around High Wycombe are congested.
Traffic Link estimating current travel time on the M40 is 60 minutes.
London Road is very busy as cars are diverted off the M40.
Police are advising motorists to avoid that area at the moment.
Traffic is being diverted by police.
Mr Williams said the M40 is closed in both directions at Junction 4b and he believes it is closed to Junction 3 (Beaconsfield).
Police say a man is the wrong side of the barriers at a bridge in Cressex Road, High Wycombe.
Thames Valley Police spokesman James Williams said police were called at 1.56pm to reports of a man on the wrong side of the barrier on the bridge over Cressex Road, High Wycombe.
The Bucks Free Press is waiting for an update from police about the incident. More to come as we get it.
Unconfirmed reports suggest there is a man threatening to jump off a bridge onto the motorway.
The M40 is closed in both directions at the Handy Cross junction.