Retired engineering lecturer Bob McFarlane had tried to open an investment Isa with the company in August, but his attempt to open the Isa was refused after he revealed his date of birth.

Mr McFarlane told The Herald: “I had a cash Isa which was maturing in August. I could have put it back in for 0.6 per cent interest but I used to have an investment Isa with Scottish Widows so I phoned them and told them I was interested in a stocks and shares Isa. They said that’s okay and took my details but when my date of birth came up they said ‘we can’t do business with you because you’re over 74”.

When Mr McFarlane complained to Scottish Widows, the company reiterated its policy in writing, where it confirmed that “the maximum age of entry for our stocks and shares Isa is 74”.

After the incident, details of the letter were published in The Herald. Following this publication, Scottish Widows re-contacted Mr McFarlane to tell him he had been given “incorrect information in regards to taking out new stocks and shares Isa with Scottish Widows”.

Complaint manager Jenny Vincent said: “Having fully reviewed this matter, it is clear that we have not provided you with an acceptable level of service and your complaint has been upheld. I am so sorry that we led you to believe that an age restriction was linked to this product and for how this would have made you feel.

“The product itself does not have an age restriction, however, we are only able to offer advice and proceed with telephone applications for customers under the age of 74. We should have explained this to you previously and also made you aware that you could seek independent financial advice in order to take out the new policy with us.”

Scottish Widows has since compensated Mr McFarlane, sending him a cheque for £100 in recognition of the fact he had not been provided with “an acceptable level of service”.

The company also sent him a pack containing details of the various investments he could make within its Isa wrapper, though stressed that this is not normal practice.

Ms Vincent wrote: “This is outwith our normal process and is the documentation that we would send to customers under age 74 who contact us by telephone To clarify, we have provided you with incorrect information in confirming that the maximum age of entry into our stocks and shares Isa is 74.

“Whilst we would not have been able to offer you advice or send you the information in writing on verbal request, we should have explained to you that the product was available through seeking independent financial advice. We have made a concession on this occasion to provide you with the paperwork, given the poor service you have received and the incorrect information you have received.”

As a consequence to the incident, Mr McFarlane, who initially chose to keep his money in a low-interest cash Isa from Bank of Scotland, has said he is still considering whether to invest his money with Scottish Widows.

He has also said he will donate the £100 compensation money to charity.

A spokesperson for Scottish Widows, said: “We’re sorry for the service Mr McFarlane received. This is an important decision, particularly for potentially vulnerable customers. We should have explained that the investment product he was looking for was only available with financial advice.”