A former rail minister says a link to Birmingham from the North West is "the real prize".
The MP for Bexhill and Battle announces he will not stand at the next general election on 4 July.
Bexhill MP Huw Merriman is holding the meeting despite a decision on the site still not being made.
Council officials say they are "disappointed" not to be told by the Home Office about the purchase.
The government wants to turn a former prison near a housing estate into asylum seeker accommodation.
The government has been exploring options to help the city's regeneration, the rail minister says.
The Cambridge South station is being built near the city's Biomedical Campus.
Sussex Police said 76 minors housed in Hove were currently missing.
The rail minister agrees with the opposition that "we cannot continue like this" over rail delays and says reforms are needed.
