Companies are being urged to take advantage of the Annual Investment Allowance, which allows businesses to claim tax relief on allowable capital expenditure of plant and equipment, including vans, before it reduces substantially from 1st January, 2016.
The Annual Investment Allowance enables a business to claim tax relief on purchased capital equipment during each tax year, and there has been a temporary level of £500,000 in place since April 2014. 
However, that figure is being reduced to a permanent level of £200,000 from 1st January, 2016, so capital equipment requirements should be considered before the end of 2015.
Only vans that are purchased are allowable under the Allowance, but that includes vans that are financed using hire purchase or contract purchase. Leases do not qualify.