An IT failure at stock broker Saga Share Direct has prevented customers from buying and selling investments, with many forced to wait in long telephone queues to make trades.
The Isa and investment trading brand used to be owned by the Saga Group, the financial services brand that specifically caters for the over-50s. It was recently acquired by Equiniti, another trading company.
A spokesman for Equiniti said the problems arose from a "third party software failure" and customers should use the company's phone line to make trades.
However, customers have reported long queues in order to make basic trades. One user, from London, was unable to trade today as markets were rising after being forced to wait for more than 20 minutes.
“I wanted to trade easyJet shares which had been rallying. In total they jumped 7pc and I missed an excellent opportunity," he said.
A regular trader, he added: “This is a big deal for me and it is outrageous that they have failed investors in the current environment."
The Equiniti spokesman said: "These phone lines have had a wait time of under three minutes."
Saga Share Direct allows customers to buy and sell investment using its currently defunct website and phone. Phone trading normally costs between £12.50 and £25 per trade, but the higher fees were waived during the problems and customers were charged online trading costs of between £9.75 and £11.95 instead.
A message on the website said: "The Saga Share Direct website is currently unavailable and we are working to restore it as soon as possible."
Saga could not be reached for comment.