The Western Front Association have posted an update to last year's announcement that they've acquired a collection of 6.5 million British WW1 pension cards:
Other Ranks Died (this contains nearly one million individual records)See an explanation and examples at
Widows and Dependents of Other Ranks Died (in excess of one million records)
Other Ranks Survived: Requested/Rejected/Receiving Pension (over 2.5 million records)
Officers survived and Officers' Widows (approximately 150,000 records)
Merchant Naval Cards (about 5,000 records)
Thanks to Glenn Wright for the tip.