By Angela Harrison
BBC News Online education staff
An exam board has changed some GCSEs after copies of exam papers were found in a street.
A bundle of exam papers was discovered in a street by a member of the public.
Some papers were missing.
The Oxford Cambridge and RSA Examination Board (OCR) has pulled the papers, which were due to be taken next week by about 85,000 candidates, and replaced them.
The subjects involved were GSCE chemistry, science, maths and English.
Candidates at 778 schools and colleges were due to sit the exams next Monday and Tuesday.
The exam board has sent out replacement papers which are all coloured pink, to replace the original ones, which were either ivory, green or white.
The new exams had been prepared for next year.
OCR says for security reasons it cannot give more details about when and where the exam papers were found.
It did say the parcel had been delivered to an address and was signed for - but not by the person who was meant to do so.
The parcel of exam papers was supposed to have been delivered by a commercial company to an examination centre.
A spokesman for OCR said: "Any breach of security can disadvantage candidates taking exams, which is why we take such matters extremely seriously."
He said the board was extremely grateful to the person who handed in the parcel.
The replacement of the papers will cost £63,000.
The GCSE papers involved are:
Chemistry 1981/01 & Science Double Award A 1983/03 (common material)
Chemistry 1981/02 & Science Double Award A 1983/04 (common material)
Science Single award A 1984/03, 1984/04
Mathematics A syllabus - three papers
English 1500/02 (speaking and listening, reading and writing)