The General Register Office has launched its own version of birth indexes, 1837-1915, and deaths indexes, 1837-1957. See www.gro.gov.uk/gro/content.
These indexes have been created independently from other online indexes. They were made from the register images, so avoiding errors you may find on other genealogical websites (although they may have made new ones!).
The new indexes are significant as they are the first to include the mother’s maiden name before 1911 and ages at death before 1866. This will make family history research easier, No more buying a death certificate not knowing if the age matches your ancestor.
A downside to the indexes is that they will only allow a search for a given year plus two either side.
In the future they should be extending the indexes available and adding an option to purchase the certificate as a PDF. This is currently being trialed.