[JadeFalcon]

i think you will find it is illegal to share customers details with anybody unless you have given strict permission to give that information out due to the data protection act, that is why you get tick boxes on applications and such stuff that allow you to opt in or out of having your details released to a 3rd party, as an opt out this would, imho, be illegal as it is in direct breach of the data protection

article 59 of the data protection act follows (have bolded the main points)--------

59 Confidentiality of information

(1) No person who is or has been the Commissioner, a member of the Commissioner’s staff or an agent of the Commissioner shall disclose any information which—
(a) has been obtained by, or furnished to, the Commissioner under or for the purposes of this Act,
(b) relates to an identified or identifiable individual or business, and
(c) is not at the time of the disclosure, and has not previously been, available to the public from other sources,
unless the disclosure is made with lawful authority.
(2) For the purposes of subsection (1) a disclosure of information is made with lawful authority only if, and to the extent that—
(a) the disclosure is made with the consent of the individual or of the person for the time being carrying on the business,
(b) the information was provided for the purpose of its being made available to the public (in whatever manner) under any provision of this Act,
(c) the disclosure is made for the purposes of, and is necessary for, the discharge of—
(i) any functions under this Act, or
(ii) any Community obligation,
(d) the disclosure is made for the purposes of any proceedings, whether criminal or civil and whether arising under, or by virtue of, this Act or otherwise, or
(e) having regard to the rights and freedoms or legitimate interests of any person, the disclosure is necessary in the public interest.
(3) Any person who knowingly or recklessly discloses information in contravention of subsection (1) is guilty of an offence.

also section 55

55 Unlawful obtaining etc. of personal data

(1) A person must not knowingly or recklessly, without the consent of the data controller—
(a) obtain or disclose personal data or the information contained in personal data, or
(b) procure the disclosure to another person of the information contained in personal data.
(2) Subsection (1) does not apply to a person who shows—
(a) that the obtaining, disclosing or procuring—
(i) was necessary for the purpose of preventing or detecting crime, or
(ii) was required or authorised by or under any enactment, by any rule of law or by the order of a court,
(b) that he acted in the reasonable belief that he had in law the right to obtain or disclose the data or information or, as the case may be, to procure the disclosure of the information to the other person,
(c) that he acted in the reasonable belief that he would have had the consent of the data controller if the data controller had known of the obtaining, disclosing or procuring and the circumstances of it, or
(d) that in the particular circumstances the obtaining, disclosing or procuring was justified as being in the public interest.
(3) A person who contravenes subsection (1) is guilty of an offence.
(4) A person who sells personal data is guilty of an offence if he has obtained the data in contravention of subsection (1).
(5) A person who offers to sell personal data is guilty of an offence if—
(a) he has obtained the data in contravention of subsection (1), or
(b) he subsequently obtains the data in contravention of that subsection.
(6) For the purposes of subsection (5), an advertisement indicating that personal data are or may be for sale is an offer to sell the data.
(7) Section 1(2) does not apply for the purposes of this section; and for the purposes of subsections (4) to (6), “personal data” includes information extracted from personal data.
(8) References in this section to personal data do not include references to personal data which by virtue of section 28 are exempt from this section.