Payment due

After 42 years underground, Ken Herdman at 74 is trapped on the ground floor of his small home in the former pit village of Seven Sisters up the Dulais Valley in south Wales.

He talks fitfully through wheezes, gasping into his medication mask, another one hanging nearby from an oxygen cylinder, his wife hovering constantly in support. If he goes to the bathroom or moves to the dinner table he takes ages to recover from the effort.

When I visited him I was in the happy position of bringing news of a substantial payment for his crippling bronchitis and emphysema. He is owed this because his former employer, British Coal, failed to protect him from dangerous, dusty conditions. Across Britain there are tens of thousands of other former miners suffering from lung disease or vibration white finger. And, like him many have waited a very long time for compensation. Many are still waiting.

There are a quarter of a million claimants and the number has been rising at the rate of 1,000 a week, making this the biggest compensation claim in the history of Britain (and maybe the world). Over £2bn has been set aside by the government - and this is not capped so it too could rise.

On lung disease, progress has been desperately slow because the system of medical assessment to deliver fair payments is fiendishly complex. It was required to reflect the ruling by Mr Justice Turner in 1998 following a lengthy court action brought against the last Tory government and British Coal which had resisted the miners' claims for justice.

Then followed an additional 18 months of legal wrangling. Every major improvement requires agreement between the department and solicitors on both sides whose legal fees could rise to £250m. For a long time there was an adversarial relationship between the government and the miners' solicitors but, fortunately, cooperation is now good.

But it is important that the scheme is operated fairly. Taxpayers would demand nothing less. The non-smoker who has worked underground for 40 years deserves much more than the 40 cigarettes a day man who has worked below for just a year. So procedures are needed for accurate individual assessments.

The compensation scheme has been bedevilled by other problems. Both solicitors and the medical assessment contractors, Healthcall, for various reasons failed to prioritise the oldest and sickest miners. Younger, fitter men have been processed first while others tragically died. There have been long delays and mix-ups between all the key players: also mix-ups by the claims handlers, IRISC. Solicitors have been swamped by the number of claims. The government has also made mistakes.

A shortage of respiratory consultants has added to the delays. Their professional assessment includes checking pages of records on a CD-rom which for each individual can run to more than 800 pages.

And the records are often hard to trace. Teams of Land-Rovers with scanners comb the countryside, calling at surgeries and hospitals. Sometimes notes go back decades in traditional doctors' scrawl. In the mining archives at Cannock there are 30 miles of files from long-closed pits, many not even indexed and just dumped after privatisation.

Nevertheless, we have ensured that payments are now flowing more quickly, at the rate of £1m daily, and soon to rise; £360m has been paid out so far, injecting huge spending into deprived coal communities - amounts like the £140,000 recently paid to a south Wales widow or £124,979 to a Valleys miner.

But this is still not good enough. We recently cleared £400m to compensate former miners or their widows for the loss of pension entitlements because of early retirement due to illness. An additional £30m has been set aside for £2,000 interim payments to widows and between £7,000 and £14,000 to emphysema victims with asthma.

I have also asked that the oldest and those most ill are given priority. Younger and fitter men finding that their appointments have been rescheduled, I am sure will agree that men in their 70s and 80s - who can hardly breathe or move and some who may die soon - should go ahead.

We are streamlining the medical assessments. Now we not only have the capacity to do 1,000 per week but are also close to having the necessary resources in place too. This will double the rate we were achieving last year. But it will depend on finding enough doctors. I have appealed to respiratory consultants to come forward - out of retirement We have been opening new test centres.

The medical assessors, the claims handlers, solicitors and government officials have all learnt painful lessons of implementing a scheme more than double the estimated size. Over the next three months a backlog of 1,000 medical assessments each week will be progressed for payment.

We have a debt to pay to the men who worked in this country's coal mining industry and the widows who nursed them. We must all ensure they receive it.

• Peter Hain is minister of state for energy