South Mimms Services is operated by Welcome Break and sits at Junction 23 of the M25, where the motorway meets the A1(M), the A1 and the A1081.

Location

You do have to fully leave the motorway to get to South Mimms, which puts some drivers off, but there is very little in it. The services are on the exit roundabout itself, so you are off, parked and back on again quickly. It is a world away from the sort of stop where you spend five minutes working your way round a retail park.

What makes it genuinely useful is the position. It sits right at the start of the A1(M), so it works just as well as a first or last stop for anyone heading north as it does for drivers going round the M25. Junction 22 at London Colney is 2.7 miles anticlockwise and Junction 24 at Potters Bar is 2.6 miles clockwise.

Facilities

The choice here is better than most. Food and drink runs to Starbucks, Pret A Manger, Subway, The Good Breakfast, Taco Bell, Burger King, KFC and a Pizza Express in its own building outside the main terminal. For shopping there is a Waitrose and a WH Smith.

The building itself is bright and airy with a big curved roof, and there is plenty of seating. When we visited there was a yellow piano out on the concourse for anyone who fancied a go.

There is a Ramada hotel on site and fuel is BP.

EV drivers are very well served. South Mimms has a large Applegreen Electric fast charge hub with bays numbered into the twenties, the newest of them rated up to 360kW and the older units up to 175kW. There is also a Tesla Supercharger on site. If charging is what decides where you stop, this is one of the stronger sites on the M25.

Interesting Features

This is the best thing about South Mimms and almost nobody stopping here knows it is there. Walk up the side of the Pizza Express and you come to a picnic area that leads straight into Wash Lane Common, a proper nature reserve on the doorstep of the services.

It is reached through a rather good decorative metal gateway, and there is a 500m easy-access trail with benches and picnic tables along a stream called the Mimmshall Brook. The information board describes it as “a wild and undisturbed space where you can escape the bustle of the neighbouring motorway services” which is exactly what it is.

There is history in it too. Before the St Albans Road was built in 1826, Wash Lane was on the route of the main coaching road from London to Holyhead, and the bridge on the common dates from 1775. So travellers have been breaking their journey on this spot for a great deal longer than the M25 has existed.

If you have children in the car, or a dog, or you have simply been sat still for two hours, this is far better than another lap of the car park.

South Mimms Services Overall Rating

South Mimms gets 8/10. A strong range of food, a Waitrose, excellent EV charging and a nature reserve out the back make it one of the better stops on the M25. Having to leave the motorway completely is the only real mark against it, and it barely costs you a minute.

Alternative Places to Stop

There is honestly not much reason to look elsewhere here, but if the services are busy there is a Tesco Express about a mile and a half away towards Potters Bar, along with a row of takeaways and a couple of Autel charge points a little over a mile from the junction.