Starting a savings account for a child and contributing regularly is one of the most powerful financial gifts someone can give. The magic of compounding returns means that even a modest sum every month has the power to turn into a large portfolio.

Doug Robertson, 75 from Cumbria, has been contributing £200 a month for more than a decade into Child Trust Funds for his two grandchildren. He has been investing everything into the Aviva UK Index Tracking fund, which owns Britain’s 600 largest companies.

Now aged 14 and 12, the portfolios are worth about £30,000. But they could have been worth far more if they were invested more globally. The UK market, including dividends, has more than doubled in the past decade but the global market, which is dominated by large American technology stocks, is close to quadrupling .

“Have I been invested in the right market? There are still a number of years before my grandchildren turn 18 and get hold of their money and I want it to grow as much as possible before then,” Mr Robertson, a retired operations manager, said.

He is also concerned that Child Trust Funds, which were offered to babies born between September 2002 and January 2011 and came with a £500 bonus from the government, are not the right place for the money.

“Should I change them to Junior Isas so that they convert into an adult Isas at 18? They are held with Foresters Financial, a wealth manager, and I am concerned that the annual 1.5pc fee is too high,” he said.