law: Arbitration Act 1940
  Section 7
  Arbitration Agreement.
  (1) In this Part, "arbitration
  
  agreement" means an agreement by the parties to submit to arbitration all
  
  or certain disputes which have arisen or which may arise between them in
  
  respect of a defined legal relationship, whether contractual or not.
  (2) An arbitration agreement may be in the
  
  form of an arbitration clause in a contract or in the form of a separate
  
  agreement.
  (3) An arbitration agreement shall be in
  
  writing.
  (4) An arbitration agreement is in writing if
  
  it is contained in -
  (a)  a 
  
  document signed by the parties;
  (b)  an 
  
  exchange of letters, telex, telegrams or other means of telecommunication which
  
  provide a record of the agreement; or
  (c)  an 
  
  exchange of statements of claim and defense in which the existence of the
  
  agreement is alleged by one party and not denied by the other.
  (5) The reference in a contract to a document
  
  containing an arbitration clause constitutes  an arbitration 
  
  if the contract is in writing and the reference is such as to make that
  
  arbitration clause part of the contact.