The accounts for the year to the end of March 2016, released on Tuesday, show grant awards were worth £583m against a budget of £698m, compared with awards of £1bn in the previous year.
The accounts say that the large reduction was "due to the timing of grant decisions and does not represent an ongoing change in our capacity to make grant awards".
They also say the 2014/15 grant awards were unusually high in part because of the £149m given to set up the grant-making foundation the Power to Change Trust.
Delays to the BLF’s European match funding programme also resulted in a lower than anticipated total of grants in 2015/16.
Total expenditure was £715m in 2015/16, down from £1bn in the previous year, with the fall in grant expenditure accounting for much of the reduction.
Income fell slightly from £846m to £820m, mainly due to a reduction in proceeds from the National Lottery (from £783m to £769m) and a fall in dormant account money income (from almost £50m to £37m).
The largest single award made in 2015/16 was £33m to the Royal Society of Wildlife Trusts. Overall, 11,779 awards were made in the course of the year, with 89 per cent of those worth less than £10,000.
The Big Lottery Fund had a surplus of £105m in 2015/16, after a deficit of £169m in 2014/15, according to the accounts. The BLF’s cumulative deficit at 31 March 2016 was £769m, down from £874m.
The BLF’s accounting policy means it treats awards as expenditure as soon as they are approved, the accounts say, and the fund manages its long-term cash flow based on grant cash commitments and projected incomes rather than an annual surplus or deficit.