Many retailers believe incidents of violence against staff could increase because of the government's failure to clearly publicise the age change.
Retailers across the country were forced to devise their own methods of promoting the change. Independent retailer Lesley Brown, who owns Frankmarsh Stores in Barnstaple, Devon, painted details in her store window along with a countdown to the October 1 deadline. She has also arranged a meeting with the local Co-op store to share information on local teens who might attempt to buy tobacco.
The Association of Convenience Stores (ACS) labelled the government's advertising campaign as "woefully inadequate". While the age change was officially announced on January 1 this year, an outdoor advertising campaign did not begin until late September.
ACS chief executive James Lowman said: "The risk that low awareness presents is that people will blame the retailer for refusing to sell them a product they were previously able to buy. This will lead to abuse, intimidation and even violence. We call on the government, police and the wider community to support retailers in not tolerating any such behaviour as a result of the change in law."
Ready to Roll: how retailers are coping with the new tobacco lawsArjan Mehr, Londis, Bracknell, Berkshire
"A lot of young people are genuinely ignorant of the age change. The true impact is yet to be seen, but I hope we've prepared ourselves for the change. I don't believe the government did enough to advertise the new laws. There should have been ads between relevant TV programmes and in newspapers."
Sally Stringer, Beckford Stores, Beckford, Devon
"We've had no support at all from the authorities to help enforce the change, but you can be sure Trading Standards will be the first to jump on us and send in 16-year-olds to do test purchases. It's just a way of getting money out of retailers."
Mark Cleary, Spar, Manchester
"We adopted a Challenge 21 policy a few months ago to prepare the local kids for the change and it has been pretty effective."
Meta Patel, Mace Express Bow, London
"We have been telling all the local kids about the change for a couple of months now so they are all well aware of it. We have also received a lot of help from our local authority who sent someone over to offer us advice. They also gave us some extra posters to put in the window."
Geoff Garrad, Tates Spar, Aberystwyth
"We've had no problems and I'm confident my staff will take it in their stride, but only because we've prepared well. We've had to do all the groundwork ourselves, though."
Lesley Brown, Frankmarsh Stores, Barnstaple, Devon
"We will cope with the change, but the only reason is because we've carried out our own awareness drive. The government hasn't advertised the change enough. I was also disappointed to see only a few newspapers carried a small piece on the age change."