Since Questor first advised readers to buy Intertek just over a year ago, the FTSE 100 member’s share price has surged 23pc higher. In doing so, the provider of testing, assurance and inspection services to a wide range of industries has outperformed the index by 20 percentage points. When dividends received since our original tip are added to its performance, the company has produced a total return of around 26pc. Clearly, many investors are likely to be tempted to bank their profits and sell the stock after generating a substantial return in a relatively short space of time. After all, the world economy’s prospects remain highly uncertain as interest rate cuts are delayed in the US, China’s property sector continues to struggle, and Europe and the UK produce extremely disappointing rates of GDP growth. Moreover, geopolitical threats are elevated, with the ongoing war in Ukraine, conflict in the Middle East and tensions in Asia having the potential to prompt significant share price declines over the short run. However, Intertek continues to offer significant long-term investment potential. The firm’s latest annual results, released last month, showed it is making encouraging progress in delivering on its growth strategy. Sales rose by 6.2pc...