Clothing and footwear sales saw double-digit like-for-like growth in the first week of the month as customers bought autumn and winter collections, but faded as they were too nervous to fill their wardrobes with them.
David McCorquodale, head of retail at KPMG, said October sales figures had been like a "disappointing firework - full of promise, but eventually fizzing out with a whimper" and said winning a share of the Christmas wallet over the next two months would be just as competitive as last year.
More top news
ITV News correspondent Duncan Golestani pays tribute to a fearless young Kurdish journalist he trained in Iraq.
ATM machines were affected, while people also reported problems using cards in shops.
Representative Darrell Issa, who is from California, has said there should be a special prosecutor investigating Russian hacking and Trump.