Tom Alexander will be retained in an advisory role as a consultant to Virgin Mobile for the rest of the year, but he will be superseded by Alan Gow, who is currently CFO, when Virgin Mobile becomes part of NTL on July 4.

The departure of the chief executive is not the only boardroom change at Virgin Mobile. Non-executive chairman Charles Gurassa will also step down, as will a host of other non-executive directors including Gordon McCallum, Caroline Marland, Rupert Gavin, David Maloney, and Richard Huntingford. Fellow executive director and co-founder Joe Steel will remain with Virgin Mobile in the role of commercial director and deputy managing director.

Since we launched Virgin Mobile in November 1999, the business has proposed enjoying rapid growth and now has more than 4.3 million customers, said Alexander in a statement to the London Stock Exchange. I have loved every minute, but now is a good time for me to take a break. The company has a terrific track record and now an exciting future with NTL, and I wish my colleagues every success in the years ahead.

The acquisition of Virgin Mobile allows NTL to offer the first quad-play (mobile phone, fixed-line, pay TV, and internet access) service in the UK.

NTL’s pursuit of Virgin Mobile began last December when NTL offered 323 pence ($5.61) in cash for each Virgin Mobile share, a 3.9% premium on Virgin Mobile’s closing price the day before the deal was announced.

The deal had been eagerly backed for the past four months by Virgin Mobile’s largest shareholder, the British entrepreneur Sir Richard Branson, who has a 72% stake in the operator. However, the small premium did not impress Virgin’s minority shareholders who between them controlled 28.5% of the operator, and they quickly rejected the initial offer. Takeover talks dragged before agreement was finally reached in early April.

It is not hard to see why Virgin Mobile is so desirable to NTL. The Trowbridge, UK-based mobile operator has an incredibly strong brand name, and it is also recognized as having excellent customer service. These two points have been well-documented problem areas for NTL for years now.

Alexander oversaw the operator’s flotation on the London Stock Exchange in 2004, which netted it approximately 800m pounds ($1.5bn). In 2005, Alexander was paid 297,000 pounds ($559,681), and he made more than 10m pounds ($18.8m) from the flotation.

Speculation had been rife that Alexander would leave, especially after he told The Daily Telegraph newspaper last November that it would be harder for the operator to keep its entrepreneurial spirit alive if a large predator took over.

Shares in Virgin Mobile dipped 0.13% to 373.5 pence ($7.04) on the London Stock Exchange following the announcement.