if i have a truck/van license in the uk does it mean i can drive a car as well?

Yes.

We don't have "truck/van" licences (note UK spelling).

The standard full UK driving licence entitles the holder to drive vehicles up to 7.5 metric tonnes and minuses of up to 3.5 tonnes with 8 passenger seats, although some licences may restrict that in various ways (e.g. if the holder passed their test on an automatic transmission vehicle, then that's all they can drive). Drivers with older licences usually have D1 category automatically included which enables them to drive minibuses with up to 16 passenger seats.

I've oversimplified it a bit for brevity, but if any driver holds a licence to drive larger commercial vehicles then they'll only have obtained it if they already hold a regular driving licence, so will be able to drive cars as well.

Yes says it all

There is only one type of driving licence in the UK, and it lists the categories of vehicle you are allowed to drive. If it says B on your licence, you can drive a car.

In the UK you get one license and onto that are added the classes of vehicles you can drive. Car, Motorcycle, trailer etc. Here there is a distinction between Automatic and manual transmission as well.
Here we have a whole list of license classes all of which include driving tests to get the class added Lose your license it all goes.