Noticed the last couple of weeks a lot of arrow signs have appeared all over, but no indication what for. First I thought it might be some sort of race, but having driven to work last week they go down the A1 to at least Mill Hill. They don't look like official diversion signs. There are some pointing around the South Mimms roundabout town the exit from the services and towards Potters Bar town.

Anyone know what they're for?