Hyndburn's parliamentary constituency could be carved up under new plans unveiled this week.
A new study projecting electoral boundary changes has put Accrington in the same seat as Rawtenstall, with Great Harwood and Rishton annexed into Blackburn.
The coalition government has secured a deal to cut the number of MPs from 650 to 600, and redraw seat boundaries.
Three models have now been produced to forecast how the seats may be carved up, with the final new map due to be drawn up by the four Boundary Commissions in September.
And current Hyndburn MP Graham Jones believes the independent report - by Democratic Audit - will not be far wrong in its forecasts.
It would create a constituency spanning from Rawtenstall to Altham, with just over half the electors covered by Hyndburn Borough Council and the rest lying in Rossendale. Netherton, Overton, Rishton and St Oswald's wards, meanwhile, would move into a Blackburn constituency for parliamentary elections.
If this were implemented it would lead to an enlarged constituency of some 77,434 electors, around 8,000 higher than Hyndburn and Haslingden.
Mr Jones said that would mean more work for its MP, and who would have to split their time between two council boroughs.
The report’s authors have underlined that their model cannot be read as a prediction of what the Boundary Commissions will propose.