'What's that smell? Oh, yeah, money!'

My first thought was that some farmers are going to do very well selling the odd field or two to developers.

Most busy motorways have enough already. I guess it's the quieter areas that will benifit. I know I'd have liked a shorter distance between service stations when I've been driving past the lake district at night on the M6.

There are some areas with few services. Like around the M25.

That's true, I'd forgotten about the M25. There's not a single one between the M1 and Heathrow.

The only one I know of is in Kent between the M23 and the Dartford tunnel.

Is it the M40 that has no services anywhere along it's entire length? May not be true now but was a while ago.

Yes it and the connecting motorway to the M5 and M6. I am not sure if there are many on the M11 either.

M25 has services at South Mimms, Thurrock (there is a service station there as well as Lakeside), and Clackett Lane.

From memory, the M40 has services at Beaconfield, Cherwell Valley and Warwick.

[Edit] A quick search reveals there's a fourth at Oxford

Well they must have been added since my last drive along the M40.

Must have been a while ago because I've been driving up and down the M40 regularly since 2006.

I remember the Oxford one being built. I was thinking it was recently, but actually it may be well over 10 years now. It wasn't there when I lived in Oxford, but I moved 15 years ago...

There are a lot more than there were when I did most of my driving back in the 90s.

Generally I think more is better. There isn't really any competition at the moment, and it makes it more convenient. Although prices will always have to be high because of the running costs - all those lights need power and the toilets need full time staff to clean them. Remember when you buy that sandwich, you're also paying for all the people that stopped there just to use the loo...

Beaconsfield - Junction 2 - built 2009
Oxford - Junction 8a - built 1998
Cherwell - Junction 10 - built 1994/rebuilt 2011
Warwick - Junction 12/13 - built 1994

I've used the first three on my travels, though tend to use Cherwell if anything. On my own travels, I've always preferred the option of pulling over every 20-30 mins if needed so perhaps on that basis, it could almost be "mandatory" to create service stations. The problems are: too many and you'll get dilution of customers (so instead of all coming off at one service station, some go to the first, some the second etc), and throughput (some areas have very little traffic and it would be unprofitable to open a business there).