I wouldn't drive it with no tax.
A few years ago I bought a car from my next door neighbour. Because it needed a couple of jobs, it sat on my drive for a while. Eventually the jobs got done and I was ready to tax it. My plan was to drop the kids at school and tax it on my way to work. Sadly, this coincided with a VED clampdown in my area. I parked the car near school and when I returned to it, a nice police officer had blocked it in with his bike and had summoned a tow truck from the agent employed by DVLA. The basic gist was that unless I paid the agent £200 on the spot (cash or card), he would be loading up my car and taking it back to their storage yard. £120 of the fine is refunded when you tax the car (you have to go to the yard and you wouldn't believe the stuff they've lifted for tax, MoT and insurance indiscretions). If they take it they charge you for towing it, plus storage, plus the fine. No exceptions, no arguments.