South Mimms services at J23 is an International haulier covid testing/documentation centre.

On top of which I know that las friday the M"% was the usaual friday afternoon chaos.

There has also been a lot of work in the roundabout area, hard shoulder widening etc on the eastbound M25 just passed the motorway exit. This has meant narrow/single lanes, very short traffic lights. Been going on for ages. Never seen a single worker doing any work though...

Plus of course--people are beginning to go to work now-by car and not public transport ,then add in holiday folk heading from the north to the east coast or over the Dartford bridge towards the south.

Avoid if you can-or travel at night. It'll never get better here--a serious black spot

If joining the M25 from the north, consider these alternatives to J23 (South Mimms).

For eastbound (clockwise) onward travel, get on to the M11 and join the M25 at J27.

For westbound (anticlockwise) onward travel, leave the A1(M) at Hatfield (J3) and go west on the North Orbital (A414), joining the M25 at J21a - this saves a few miles in any case.

Came down from Lincolnshire on the A1, from the slip road off the A1 to getting on the M25 took about two hours....is this normal there or was it just one of those things? Just seemed seemed a series of roundabouts and lights but couldn't see much due to so many lorries blocking everything out.

One of the problems is that the area is a well-known bottleneck, because the A1 from the South Mimms/M25 junction to the Hatfield tunnel/North Orbital (towards St. Albans/Watford) is all two lane only, going down from three.

A similar jam nearly always happens when the road goes back down from three to two lanes as it passes Stevenage (Lord knows why it's the case in both circumstances, as there's more than enough room to (and plans in place) to have three lanes each way.

When I was working in Stevenage, in the morning rush hour it often took me twice as long (30 mins) to drive from one end of the town to the other (whether on local roads or the A1 between J9 and J7 - both about 5-6 miles) as it did twice the distance to J9 along the A505 from home.

The A1/M25 junction is made all the more busy by it not having direct slip-ons/offs from the both roads to the other, with a large traffic-light controlled roundabout AND the only motorway service stop for a long way on each road.

As others have said, if you have to travel during the peak rush hour times, plan your journey in good time to avoid the area. Other routes won't be empty, but accidents aside, they will be somewhat better, but not great. Unfortunately Hertfordshire isn't well served with East-West trunk roads, so you often have to make do with the proverbial lesser of two evils when travelling in the rush hour, or just leave earlier.