In England the common-law requisites of a guarantee in no way differ from those essential to the formation of any other contract. That is to say, they comprise the mutual assent of two or more parties, competency to contract, and, unless the guarantee be under seal, valuable consideration. An offer to guarantee is not binding until it has been accepted, being revocable till then by the party making it. Unless, however, as sometimes happens, the offer contemplates an express acceptance, one may be implied, and it may be a question for a jury whether an offer of guarantee has in fact been accepted. Where the surety's assent to a guarantee has been procured by fraud of the person to whom it is given, there is no binding contract. Such fraud may consist of suppression or concealment or misrepresentation. There is some conflict of authorities as to what facts must be spontaneously disclosed to the surety by the creditor, but it may be taken that the rule on the subject is less stringent than that governing insurances upon marine, life and other risks (_The North British Insurance Co._ v. _Lloyd_, 10 Exch. 523), though formerly this was denied (_Owen_ v. _Homan_, 3 Mac. & G. 378, 397). Moreover, even where the contract relied upon is in the form of a policy guaranteeing the solvency of a surety for another's debt, and is therefore governed by the doctrine of _uberrima_ fides, only such facts as are really material to the risk undertaken need be spontaneously disclosed (_Seaton_ v. _Burnand_--_Burnand_ v. _Seaton_, 1900, A.C. 135). As regards the competency of the parties to enter into a contract of guarantee, this may be affected by insanity or intoxication of the surety, if known to the creditor, or by disability of any kind. The ordinary disabilities are those of infants and married women--now in England greatly mitigated as regards the latter by the Married Women's Property Acts, 1870 to 1893, which enable a married woman to contract, as a _feme sole_, to the extent of her separate property. Every guarantee not under seal must according to English law have a consideration to support it, though the least spark of one suffices (_per_ Wilmot, J., in _Pillan_ v. _van Mierop and Hopkins_, 3 Burr., at p. 1666; _Haigh_ v. _Brooks_, 10 A. & E. 309; _Barrell_ v. _Trussell_, 4 Taunt. 117), which, as in other cases, may consist either of some right, interest, profit or benefit accruing to the one party, or some forbearance, detriment, loss or responsibility given, suffered or undertaken by the other. In some guarantees the consideration is entire--as where, in consideration of a lease being granted, the surety becomes answerable for the performance of the covenants; in other cases it is fragmentary, i.e. supplied from time to time--as where a guarantee is given to secure the balance of a running account at a banker's, or a balance of a running account for goods supplied (_per_ Lush, L.J., in _Lloyd's_ v. _Harper_, 16 Ch. Div., at p. 319).