(1)This section applies where—
(a)a person is convicted of a class A drug trafficking offence committed after 30th September 1997;
(b)at the time when that offence was committed, he was 18 or over and had been convicted in any part of the United Kingdom of two other class A drug trafficking offences; and
(c)one of those other offences was committed after he had been convicted of the other.
(2)The court shall impose an appropriate custodial sentence for a term of at least seven years except where the court is of the opinion that there are particular circumstances which—
(a)relate to any of the offences or to the offender; and
(b)would make it unjust to do so in all the circumstances.
(3)Where the court does not impose such a sentence, it shall state in open court that it is of that opinion and what the particular circumstances are.
(4)Where—
(a)a person is charged with a class A drug trafficking offence (which, apart from this subsection, would be triable either way), and
(b)the circumstances are such that, if he were convicted of the offence, he could be sentenced for it under subsection (2) above,
the offence shall be triable only on indictment.
(5)In this section “class A drug trafficking offence” means a drug trafficking offence committed in respect of a class A drug; and for this purpose—
“class A drug” has the same meaning as in the [1971 c. 38.] Misuse of Drugs Act 1971;
“drug trafficking offence” means a drug trafficking offence within the meaning of the [1994 c. 37.] Drug Trafficking Act 1994, the [1995 c. 43.] Proceeds of Crime (Scotland)Act 95 or the [S.I. 1996/1299 (N.I. 9).] Proceeds of Crime (Northern Ireland) Order 1996.
(6)In this section “an appropriate custodial sentence” means—
(a)in relation to a person who is 21 or over when convicted of the offence mentioned in subsection (1)(a) above, a sentence of imprisonment;
(b)in relation to a person who is under 21 at that time, a sentence of detention in a young offender institution.