The consultation was due to close on 12 July but has been extended until 10 August.

Public health minister Anne Milton said: "We have received thousands of responses to the consultation already but we want to make sure that everyone who wants to contribute can.

"We have an open mind about the introduction of standard packaging and want to take full account of all views on the possible benefits and disadvantages of action in this area."

Mike Ridgway, who heads a group of UK packaging manufacturers lobbying against the proposals, said the support that the companies had received from its workforce, suppliers and business partners was "tremendous".

API Group, Chesapeake, Parkside Flexibles, Weidenhammer Packaging Group and Payne joined forces to oppose the proposal when it was announced in April.

Ridgway added: "We are extremely encouraged and grateful to see that the deadline has been extended and that people are speaking out to stop plain packaging, which we believe could have a hugely negative impact on the UK and could set an incredibly dangerous precedent moving forward.

"I am pleased that the extended deadline means that more people can participate in the consultation after they have had time to reflect and consider the effects of the proposal.

"I urge those who haven’t made their views felt yet to make the most of the extension so together we can quash this ill-conceived proposal that could have unforeseen and unintended consequences."

He added that concerns over the proposal document had been raised regarding the language barrier to a number of tobacco retailers for whom English is not their first language. He believes that the document is being considered for revision in alternative languages such as Urdu.

Representatives of the five manufacturers will accompany Ridgway at a postponed meeting with business minister Mark Prisk in the autumn, following the end of the consultation period, to discuss their concerns about the proposal's potential impact on businesses in the packaging sector and their employees.