Uproar followed the news on 16 May that British tourists were being shipped home from Mombasa on security advice. Tourists, inconvenienced and disappointed, were sceptical of the threat. The Kenyan government and public accused western governments of destroying their tourist industry. Within days, local media reported the loss of 4,000 jobs lost at the Coast.

Only hours later, news arrived of explosions in Nairobi. Ten Kenyans died and some 70 were injured. These indicated that the threat in Kenya presented a new and more dangerous level of lethal sophistication.

The tragedy lies in the deaths and injuries of innocent Kenyans. Their government has failed them twice over.

These events coincide with renewed public attention in Kenya to corruption scandals exposed ten years ago while I was British high commissioner, but reaching back longer. These comprised 18 dodgy contracts, almost all in the security sector, called collectively “˜Anglo-Leasing’. They illustrated how Kenyan procurement could be subverted for private gain on a huge scale, cloaked under secrecy deemed necessary for such security-related equipment. They also demonstrated how grand corruption in Kenya had become institutionalised, with contracts like these being handed on from rent-seekers in one government to the next.

The Kenyan government cannot get out of paying for these fraudulent contracts. One result of that is the government has to re-schedule part of its debt. Another is to delay Kenya’s issuance of its first Eurobond. Terrorism itself reduces confidence in Kenya further.

The dodgy contracts have delivered nothing commensurate to Kenya’s defences. Nor has the extensive foreign assistance rendered in the last 15 years. The government’s insouciance in face of the threat combines with a thin-skinned response to criticism. When 18 ambassadors signed a call for renewed efforts against graft last month, they were duly berated by President Kenyatta’s attack dogs.

The fact is that Kenya’s institutions are so corrupt that the large funds allocated over the years to security have been largely squandered. Its leadership is repeatedly embarrassed by recurrent demonstrations of how Kenya’s declarations of intent on graft fail against the engrained venality in the system. Its citizens are effectively swindled twice: their taxes stolen while their security is not one whit improved, leaving them exposed to violent criminality and terrorism, culminating in last year’s attack on the Westgate shopping mall, and now these events. The UN calls Nairobi its most dangerous posting.

Finally, no tragedy is complete without the element of farce. Nine years ago, a man called Joshua Kulei was declined a visa to visit Britain – a privilege he had hitherto regarded as a right. Mr Kulei was a personal assistant to former President Moi, and one of the iconic figures of the grand corruption associated with that regime. Although Anglo-Leasing reaches back into that era, it was not the most egregious case.

When Mr Kulei was told in 2004 that his presence in this country was not conducive to the public good it was a shock. Mr Moi rang me to intercede, in vain. As the news spread, it caused disbelief, then glee, in Kenya.

Last month, Mr Kulei again visited the United Kingdom, rejoicing at his freedom to travel here in his usual style after a denial of ten years.

The question arises, what has he done to redeem his unsavoury reputation?

I put exactly that question to my constituency’s MP, Justice Secretary Chris Grayling. The Home Office refused to confirm or deny anything out of respect for Kulei’s privacy. The Foreign Office, for its part, provided a long bromide from Mark Simmonds about the UK government’s unchanged policy on corruption in Kenya.

But something clearly has changed, and we have a right to know what. Corruption flourishes in Kenya as ever. The policy of excluding a couple of dozen luminaries of a corrupt elite has had a useful effect: it helped disrupt the corruption networks – which run through the UK, incidentally – and exposed to public ridicule those affected. It dented their confidence that they could rely on entry to the UK as a safe haven if life ever got too hot.

It signalled to Kenya’s long-suffering citizens that we were on the side of the anti-graft movement.

Our interests, like theirs, are in a government which is effective in service-delivery and especially in combating insecurity. Badly run institutions and venal leadership are a menace to these interests.

So, why has Mr Kulei been let off? What signal does his presence here send to us and to Kenya? How many more Kenyan VIPs denied visas will quietly be allowed back? Will we protect their privacy at the expense of seeing Kenya’s security attacked by dedicated terrorists who raise their game faster than the better-resourced but lumbering Kenyan state and its flawed elites?

Sir Edward Clay (British high commissioner in Kenya, 2001 – 5).