This means that you will receive 325 Virgin miles per £1 of Tesco vouchers, compared to the usual 250.
There is also a separate promotion offering 2,500 Virgin miles if you choose to set your Tesco account to auto-convert to Virgin Flying Club each quarter. I do not recommend this, though, as it is better to keep hold of your vouchers until a decent conversion bonus comes along. If you do want to do it, perhaps with a dormant Clubcard account, log-in to the Clubcard website and go ‘My Clubcard Account’ and ‘My Preferences’.
Details of the conversion bonus, and the web page to order from, are here.
If you are not familiar with Virgin Flying Club, please do NOT jump in and convert a large pile of vouchers without doing your research.
My original post on the offer is here. That post contains a substantive discussion on the pros and cons of diversifying into Virgin Flying Club alongside Avios points.