Sunday sees both the British Grand Prix at Silverstone, central England and the England-Australia one-day international cricket match at Lord's, being staged just a few days after explosions Thursday left at least 50 dead and more than 700 injured.

But displaying the kind of stoicism that has been the hallmark of the British capital's response, a sentiment to be expected of a man whose job requires him to risk his life, Formula One world champion Michael Schumacher urged the expected 100,000 sell-out Silverstone crowd to turn out in force.

"It (the British Grand Prix) is an event that has been scheduled for a long time so the security measures were already well programmed," said Schumacher.

"These days you can't be certain to be safe in any place in the world. First the Twin Towers in New York and now these horrible things that just happened in London.

"But we have to go on, always for the same reason. And that is that there are people who watch and love this sport and we need to do what's possible to give them a smile."

Next week sees the British Open golf championship at St Andrews, on the north-east coast of Scotland and close to Gleneagles where leaders of the Group of Eight (G8) of the world's leading industrial nations met for a summit this week.

Some 200,000 fans are expected during the four days of the tournament and spokesman Stewart McDougall said Friday: "The Open is definitely going ahead no question."

But New Zealand's US Open champion Michael Campbell voiced fears after speaking to a friend, involved with security at last year's Athens Olympics, who criticised safety standards at golf events.

"I am heading to St Andrews with genuine concerns. I have never had any concern but after listening to this fellow my view has changed dramatically."

At Lord's, cricket authorities were resolute ahead of Sunday's one-day international between England and Australia.

But a statement from ground owners Marylebone Cricket Club (MCC) warned the anticipated 28,000 crowd not to "leave their bags unattended at any time."

It was an echo of cautions regularly handed out during the terror campaigns of the Irish Republican Army (IRA) on the British mainland during the 1970s and 1980s.

Meanwhile England captain Michael Vaughan said victory meant little compared to the severity of what had happened in London.

"Cricket is not that important when you see those things," he said.

The attacks took place on the same day that an England and Wales Cricket Board security team returned from Pakistan where a scheduled Test match in Karachi could be cancelled because of safety fears associated with terror attacks in the region.

And nowhere is the global link between the fields of politics and sport better demonstrated than the Olympic Games.

London won the vote to host the 2012 edition on Wednesday in Singapore only for a mood of euphoria turning to grief in the space of 24 hours.

In its initial projections, the London team said it had budgeted for a 200 million pounds security spend, less than half the amount spent by Athens.

However, costs in Greece escalated after the September 11 attacks and it was British experts who provided the backbone of the Athens security operation.

And International Olympic spokeswoman Giselle Davies insisted Thursday: We have full confidence in the London authorities to secure the Games."

It was at the 1972 Munich Olympics, where 11 Israeli athletes were killed by Arab terror groups, that the link between sport and such violence first became all too real.

That same year saw Wales and Scotland refuse to play rugby union internationals against Ireland in Dublin because of IRA threats.