So I need to drive from London to Glasgow and back on the same day, should I take the M1 or M6?
Probably going next Wednesday
Any advice?
The M1 doesn't go to Glasgow, so I'd take the M6.
Just use google maps/waze for the quietest on that day. It'll do traffic etc, and probably save you some time/
M1 + A1(M)
Which doesn't go to Glasgow, it goes to Edinburgh.
It's debatable whether this is even the best route to Edinburgh let alone Glasgow. Glasgow is an easy direct 100% Motorway route up the M6 and M74 into the city centre. Parts of the other route are not even dual carriageway. I've no idea why you would consider going that way
Which doesn't go to Glasgow, it goes to Edinburgh.
It's debatable whether this is even the best route to Edinburgh let alone Glasgow. Glasgow is an easy direct 100% Motorway route up the M6 and M74 into the city centre. Parts of the other route are not even dual carriageway. I've no idea why you would consider going that way
So I need to drive from London to Glasgow and back on the same day,
M6 and take the toll
People seem to have missed the bit I bolded. Don't do it. Take a plane or train. Seriously. At 400 miles it's far too far to drive both ways in one day. At 70 mph that's 6 hours each way without breaks. You should add in at least an hour for breaks. And there are plenty of speed cameras. And there have always been plenty of roadworks / 50 mph zones. If the sleeper train is running, take that. You'll get there in the morning, be there for a full day, then be back in London the next morning.
I've done most of this trip by car a fair few times. A trip from Aberdeen to London takes me near Glasgow and takes the whole day.
At this time of year I would take the M1 then the M6 then the M74. And I would return the following day. In the summer I would go via the A66 because I get to visit where my grandmother's ashes were scattered.
Whilst I understand your point, it depends on the individual and the car.
I'm not really sure that's true. I'm no stranger to very refined and relaxing comfortable cars nor long drives but there is a reason why commercial driving is regulated to stop people doing 12-18 hour drives in a single day. It is more risky.