On 28 November 2012, HMRC issued the Value Added Tax (Amendment) (No. 3) Regulations 2012, which will come into force on 1 January 2013.
The Regulations amend UK Value Added Tax Regulations 1995, in order to implement the changes required by Council Directive 2010/45/EU of 13 July 2010, amending the EU VAT Directive (2006/112) on the common system of value added tax as regards the rules on invoicing. The amendments are summarized below.

Issuance of an invoice

The Regulations simplify the provisions relating to self-billing, i.e. a self-billing agreement will authorize the customer to produce self-billed invoices for any specified period. In addition, the Regulations remove the requirement to issue a VAT invoice for specified exempt supplies and, in case of intra-community supplies, invoices must be issued by the 15th day of the month following the one in which the goods are supplied or the services performed.
Electronic and simplified invoices
The Regulations provide for the definition of electronic invoice, i.e. an invoice that contains the particulars required and which has been issued and received in any electronic format. In order to eliminate the current barriers to e-invoicing, the only limitation on the use of an electronic invoice will be that the invoice must be accepted by the customer.
Furthermore, a simplified invoice may be issued where the consideration for a supply does not exceed GBP 250 and the supply is not made to a person in another Member State.
Time of supply and acquisition
The Regulations remove specific rules on time of supply and acquisition of water, gas or any form of power, heat, refrigeration or ventilation. Generally, the time of supply of these types of goods will be when payment in respect of the supply is received or a tax invoice is issued by the supplier, whichever is the earlier.

IBFD source