I am currently renting a flat, which has just been put up for sale as vacant possession? what does that mean?

http://dictionary.reference.com/browse/vacant+possession I would contact your landlord to find out whats going on or alternatively you could be sneaky and pose as a potential buyer for the flat and see what happens

It means that when the sale is completed the flat will be empty, no one will be living there. You need to talk to the Agent as this is untrue, as you have 10 months left on the lease. UK

"Vacant possession" means that the house will be vacant and ready for the buyer to move in on the date of closing. Therefore, if it sells, you will be notified of sale, lease termination, and notice to vacate prior to closing date. Read your lease! Normally, if there is a lease, a sale is made subject to the lease, and the new owner has to allow the current tenant to remain until the lease expires. The new owner need NOT renew or extend a lease, or allow a rollover into month-to-month tenancy at the end of the lease term. If they are advertising sale with "vacant possession," either in the terms of the lease or in law, that lease terminates on sale. Read your lease! You can expect to have only 30 days notice to vacate if that property sells since you have to vacate prior to closing.

You'd better talk to your letting agent about this. If you have a lease, you have a right to stay there unless you do something which gives them the right to serve notice to vacate.

It means that you can expect notice to quit..Get legal advice asap..................

As above, but to me is advertised falsely to potential buyers.

vacant posession meas that the owner of the flat does not live there. They own it - but they themselves do not live it it - hence it is vacant. You shouldnt worry about it too much, it will probably get sold and you will just end up paying rent to the next owner :)