Which? has launched a Stamp Out Dodgy Deliveries campaign following research showing that one in four online shoppers have had a problem with a delivery in the past 12 months.
Which? also investigated the best and worst online shops and found that B&Q's website, diy.com, is at the bottom of the pile.

The consumer champion, which polled 10,450 of its members in June and July, reveals that 60% of its respondents say one of the reasons they shop online is due to the convenience of having the product delivered, but 26% have been disappointed.

Delivery issues included parcels being late (17%), not delivered (3%) and even damaged (2%).

When asked what frustrated them, 36% said not being able to choose a suitable delivery time was an irritant when shopping online. Not being informed of the time goods will be delivered was a gripe for 26%, along with delays in receiving an item (15%) and getting goods that are damaged (11%).

Which?'s new campaign will target shops to improve the delivery service they provide. It wants retailers to provide specific time-slots for deliveries on a named day; inform customers of the estimated delivery time on the day of delivery by phone, email or text; and ask customers to specify at the time of purchase what to do if the delivery is unsuccessful.

Which? executive director Richard Lloyd said: "One of the attractions of shopping online is the convenience of having your items delivered, but we've found the experience can be anything but convenient. We want shops to do more to ensure that the service is first class, first time."

Which's survey of online shops put specialist photography retailer Wex Photographic on top with a customer score of 91%, attracting top marks for deliveries as well as product stock and the usability of its website. B&Q's diy.com scored the lowest marks, with just 47%.

However, B&Q has just invested over £60m on a revamp of its website, which it says is now the most comprehensively stocked and most functionally advanced of its kind in the UK.