Alan and Callum are employees of a listed financial services firm called Best Investment Plc. Alan comes across some information showing that the firm has made considerable losses, and the share price is likely to drop significantly when the financial reports are released in the following month. Alan immediately disposes of his shares. Callum, who is not aware of this information, decided to sell his shares at the same time to diversify his portfolio

a)Explain the offence of insider dealing

b) Advise Alan and Callum as to their legal position and advise them as to any potential defences.