The government has been accused of endangering sales in small businesses as tobacco companies reveal they are bracing themselves for enforcement of a minimum price on cigarettes.

The proposal of a set excise tax rate, which British American Tobacco and Imperial Tobacco predict could be announced by the chancellor as part of the Autumn Statement, could result in pack prices undergoing a hike to a minimum of £8.68 – an increase of almost 50% on some brands.

Ravi Kaushal, of Nisa Local in Chiswick, west London, said the move would cause small businesses to lose money.

“The chancellor has already screwed our businesses. I have no doubt it will push people towards the illicit sale of tobacco,” he said.

A spokesman for British American Tobacco said a report it commissioned from KPMG to analyse the impact of minimum pricing revealed the lowest pack price could be as much as £8.68.

“Research shows people who buy value-for-money and low-cost cigarettes are more likely to drop into the black market if you hike up prices,” he said.