6.40 Feedback. 7.5 Elements Discovered.
7.30 Handicapped in the Community.

The Embassy World Professional Snooker-Championship from the Crucible Theatre, Sheffield.
The most eventful day of the Championship as all four quarter-final matches are completed today. Two quarter-finals are continued this morning, while the remaining pair of matches finish this afternoon. DAVID VINE introduces the action. Commentators
TED LOWE , JACK KARNEHM
CLIVE EVERTON , VERA SELBY
Television presentation
KEITH PHILLIPS , BILL TAYLOR , MIKE ADLET Producers
HAZEL LEWTHWAITE , PETER HAMILTON Executive producer nick HUNTER

Policy and Practice
It would seem reasonable to close a school when numbers drop below a viable minimum. But in this re-enactment of the decisions taken by the Local Education authority in Berkshire, we see that a change in the political composition of the authority is all-important.
Producer MEG Sheffield
A BBC/Open University production

A serial in 12 episodes starring Buster Crabbe as Buck Rogers 10: Broken Barriers
In which Buck Rogers and his companions again escape from Killer Kane and return to the Hidden City, only to find that Killer Kane is menacing the City itself.
(For cast see page S3. Episode 11 tomorrow at 5.40)

Frame of the Day. DAVID VINE has the latest news and highlights.

For 900 years Lincoln Cathedral has survived earthquakes, fire and battle, to stand as a tribute to the glory of God and the skill of man. Ken Cooper and the On Location cameras tell the story of this building, and meet the people who make it ' a living cathedral '.
Producers JOHN ROONEY , ken COOPER

with subtitles, followed by Weather

Introduced by William Woollard The Oil Business
From a Forties production platform WILLIAM WOOLLARD finds out what happens to the oil on its way to the petrol pump.
Sue Baker examines the issue of lead in petrol and Whether there is a future for liquid petroleum gas as a viable alternative fuel.
The oil companies reveal their marketing plans to change the face of the garage forecourt in the 80s.
Director BRIAN strachan
Executive producerDEREK smith BBC Birmingham

The Embassy World Professional Snooker Championship
DAVID VINE introduces live coverage from one of tonight's quarter-finals. With two matches finishing earlier this afternoon, and the remaining matches tonight, this is the final ' two table' day of the Championship - and probably the most vital. Commentators
TED LOWE , JACK KARNEHM
CLIVE EVERTON , VERA SELBY
Executive producerNICK hunter

The Eurovision Final
For the first time, the winner of BBCtv's Young Musician of the Year will compete with the winner of French tv's Tournoi aes Jeunes Musiciens and with young musicians from Austria,
Germany, Scandinavia and Switzerland. Each of the finalists must be under 19, and one of them is just 14 years old.
Prizes totalling over £2,000 will be awarded by a distinguished international jury.
The programme is introduced by Humphrey Burton and Margaret Percy live from the Free Trade Hall in Manchester.
Bryden Thomson conducts the six concertos with the BBC NORTHERN SYMPHONY
ORCHESTRA, leader DENNIS SIMONS
Sound NEIL MURRAY and IAN PARR Lighting GEORGE NORTON Producer ROY TIPPING Director PETER BUTLER
For the best effect, viewers with stereo Radio 4 should turn off TV sound and position their speakers on either side of the screen, but a few feet away. Stereo headphones are an alternative.

DAVID VINE has more news and highlights from tonight's decisive World Championship quarter-finals.

Presenters PETER SNOW, JOHN TUSA and DONALD MACCORMICK bring you the major events of the day. JOAN BAKEWELL has the first news of stories from the arts; DAVID ICKE and MARSHALL LEE have the stories from behind the world of sport.

The Embassy World Professional Snooker Championship
DAVID VINE introduces further coverage of the quarter-finals-and looks forward to tomorrow's semi-finals.