M&G picks out the period January 1973 to December 1977 as a particularly difficult period to make money, and notes that £3,000 invested in its unit trusts would have produced £3,967 over the period. Fair enough, but the purchasing power of the pound fell by half over that time. Admittedly few assets then seemed capable of matching inflation. But house prices did, rising by about two-thirds - and mortgages attracted tax relief.