Could you be more tax efficient and better off?

Recent reports estimate that in the last year UK taxpayers unnecessarily paid over £12.5 billion of tax, an average of over £400 each.
Commonly such overpayments of tax arise from people failing to use all the statutory tax reliefs available to them for example, allowances such as the ISA savings allowances and the available inheritance tax reliefs.
Marshall Smalley recommends giving your tax affairs a spring cleaning before the end of the tax year to improve tax efficiency and be better off wherever possible.