Sadly the answer to your question is no. Virgin Media email is provided as a free add on to customers who have an active broadband account. Even in the days of dialup (RIP) to keep your address you had to dial in to the virgin.net system at least once every 6 months. Virgin Media do not offer a paid continuation of the email service when you leave.
Any further information is in the post that @MissPasko linked.
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