Car Lease - What is the best option?

I am wanting to acquire a new cars. Less than 160 CO. Also I am VAT registered. The car would most likely be over £12000.

What is the best way to purcashe this. I am considering  a lease as I beleive that I can claim ALL of the lease payments against tax deductions? I know that I can claim 50% of the VAT element. Or is it that I can only claim the interest element of the lease payment?