It is 100% /temz/.  I ´m from London. 

〈th〉 for /t/

Since neither /tʰ/ nor /θ/ was a native sound in Latin, the tendency must have emerged early, and at the latest by medieval Latin, to substitute /t/. Thus in many modern languages, including French and German, the 〈th〉 digraph is used in Greek loan-words to represent an original /θ/, but is now pronounced /t/: examples are French théâtre, German Theater. In some cases, this etymological 〈th〉, which has no remaining significance for pronunciation, has been transferred to words in which there is no etymological justification for it. For example German Tal ( ´valley ´, cognate with English dale) appears in many place-names with an archaic spelling Thal (see Neanderthal). The German family names Theuerkauf and Thürnagel are other examples. The German spelling reform of 1901 largely reversed these, but they remain in some proper nouns.

Examples of this are also to be found in English, perhaps influenced immediately by French. In some Middle English manuscripts, 〈th〉 appears for 〈t〉 or 〈d〉: tho ´to ´ or ´do ´, thyll till, whythe white, thede deed. In Modern English we see it in Esther, Thomas, Thames, thyme, Witham and the old spelling of Satan as Sathan. In a small number of cases, this spelling later influenced the pronunciation: amaranth, amianthus and author have spelling-pronunciations with /θ/, and some English speakers use /θ/ in Neanderthal.