Holy smoke!

[johninoz2]

Hi hope someone can help me with this one.

Have a 2003 4.4 X5, took the X5 for the normal weekend shopping run. Everything ran and felt great as normal then made one more stop in the afternoon. After a couple hours, started up the car and when pulling out of the parking lot to the main road noticed a huge cloud of smoke coming out of the rear exhaust of the car. Stopped the car - no warning lights, temperature gauge normal. Opened bonnet - no sign of anything wrong, checked oil on dipstick - looked normal and correct level. As I had the babies in the vehicle I thought I would, start up again and drive slowly to a safer spot. Again, started up with smoke coming out but as I drove slowly the smoking reduced until it seemed to have stopped. As I was close to home, I thought I would continue and risk it home. It's now parked in the garage and am hoping anyone could let me know what may have caused this, I intend to get it to the serviced first thing next week but would like to be able to do some checks before giving it out so that I have an idea what I am possibly in for. The smoke did seem white at the time but was so scared/pissed at the time, I can't be certain if there may have been a blue or gray tint to it.

Any help or advice would be appreciated.

Cheers.