The House with the High Wall by Arthur Gask

IN A WAY Robert was greatly surprised that Isaac Bannerstein had asked him to come to dinner, for all the Jew could have learnt about him must have been from the pawnbroker, and to the latter he had been only a car mechanic who was willing to work for a few shillings a day. Now, however, Bannerstein was treating him as an equal, and his very remark about dressing or not dressing for the meal suggested he was quite aware he, Robert, was by no means as low in the social scale as he had been pretending.

So, considering everything, Robert's surprise was tinged with not a little uneasiness. He was not for one moment intending to underestimate Bannerstein. The latter was a far more intelligent and subtle man than David O'Shane had ever been and, almost certainly, he would be wanting to probe far more deeply into Robert's motives in being so willing to help the pawnbroker than the latter had done. Not unreasonably, he might be suspecting there was much more in it than lay upon the surface, particularly so now that the matter of those so valuable jewels had come into the picture.