The Diary: Now it's the whites who feel put upon in Johannesburg

Jogging behind my dog in Emmerentia Park in Johannesburg early in the morning, I am ambushed by three police officers. They suddenly materialise at the top of the slope we are panting our way up, their hands raised, demanding we stop. It seems Zola - a cross between a Dobermann, a Labrador and a Pointer, and named after Chelsea's heroic playmaker - has beeped on their radar. Out of breath, I ask if the dog was speeding. No, they reply gravely, but you have taken him into an area of the park reserved for ducks and other wild animals. I apologise and lumber off.

Standing waiting beside a cluster of tall trees is an Afrikaner couple who want me to join in their bristling fury. They have just been victims of the same purge, and - perhaps because the three policeman are black - the woman is disgusted. "This government," she rages, "is abusing our human rights." Later I mention her remark to Tony Wende, a South African producer who freelances in our bureau and is known for making profound comments. "Isn't it amazing," he reflects, "that five years after Mandela came in, white South Africans are starting to appropriate the language of the anti-apartheid struggle?"

I HAVE not yet left Johannesburg for good. Everyone goes on about how the violent crime makes it one of the most dangerous cities in the world - there was clear evidence of that recently when a private firm announced it was going into business cleaning up murder scenes for the police. It said its invoices would be determined by the calibre of the bullet used and how much the victim had drunk before being shot.

But I shall still miss the city badly when November comes and I do finally leave. Miss it because of the people; especially Paulina, an easygoing and lovable 42-year-old who has worked for BBC correspondents since 1982. As I pack my cases ready to spend the coming month on Newsnight, she asks me: "Are you going to Africa?" The question underlines the fact that many South Africans regard the rest of their continent in rather the same way as Britons regard the rest of theirs. A flashback reminds me of the last thing I heard on the radio in London before I left: the DJ on Capital FM announcing proudly that competition winners would receive "a holiday in Europe".

FROM CAPE Town comes a story so unbelievable it must be true. A spokeswoman for the Pelonomi Hospital in the Free State was explaining why each week a patient had been found dead in the same bed. "Extensive checks on the air-conditioning and a search for possible bacterial infection failed to reveal any clues," she told the Cape Times. "However, further inquiries have now revealed the cause. Every Friday morning a cleaning lady would enter the ward, remove the plug that powered the patient's life support system, plug her floor polisher into the vacant socket, then go about her business. When she had finished her chores, she would plug the life support machine back in and leave, unaware that the patient was now dead. She apparently could not hear the screams over the whirring of her polisher. We have sent a strong letter to the cleaner in question."

WHEN I do arrive in London I realise I have not been in the city for more than a year, and the transition sends me into a state of mild culture shock which I try to walk off by wandering around Shepherd's Bush in circles. The first thing that strikes me is the graffiti: why would someone spray an underpass with the word FUME in huge blue letters? Why do all the aerosol- users have the same handwriting? Is there a school for them somewhere? And then there are the flyposters - on a derelict building at one end of Wood Lane is a large black-on-yellow poster declaring NIGEL DEMPSTER IS BALD, which I guess is a cult band, but I feel ashamed at having to guess.

It will sound corny, but the genuinely multicultural, multi-ethnic, cosmopolitan atmosphere I soaked up during that brief decompression session in Shepherd's Bush made me thrilled to be back in London. You don't notice race in this city - in South Africa race matters more than anything, because economics and politics have been stapled into it for so long. I tell a BBC colleague that I am amazed and delighted to see how happy people look in London; I had not remembered how happy they were, especially not in the Shepherd's Bush area. "No, it's just because the sun has appeared briefly," he points out, crushing me.

THE NEXT discovery is the amazing new BBC building in Wood Lane, a bulging edifice of chrome and green glass which I feel certain I saw spin in and out of frame during one of the battle scenes in Phantom Menace. The building is one thing - it's also my first glimpse of the boldly redesigned news programmes. Inside the Newsnight studio V S Naipaul is waiting to speak about Iran while John Prescott prepares to talk about transport.

The lights spark up, and now Mr Prescott is in animated discussion with John Redwood, who's on the line from Wokingham. The latest policy paper from the Conservatives is a blatant and wonderful piece of political opportunism in which they half-promise to flatten speed bumps, label speed cameras "taxation by stealth" and seem to give motorists a nod and a wink that under the Tories they'd be able to go like the clappers down every road in Britain. All in all, the document is proof that if anyone is getting the hang of frontline opposition, it is Mr Redwood - but he has a hard time of it on this occasion because Mr Prescott keeps shouting "Beam me up, Scotty" whenever he gets into his stride. Yes, I reflect, this is home... but not quite as I knew it.

Jeremy Vine is the BBC's Africa correspondent. From November he joins `Newsnight' as a presenter.