In England and Wales, the police cannot legally detain anyone for more than 24 hours without charging them unless an officer with the rank of superintendent (or above) authorises detention for a further 12 hours (i.e. 36 hours total), or a judge (who will be a magistrate) authorises detention by the police before charge for up to a maximum of 96 hours; for terrorism-related offences a person can be held by the police for up to 28 days before charge.
ɪn ˈɪŋɡlənd ænd wˈeɪlz, ðə pəlˈiːs kænˈɑːt lˈiːɡəli dɪtˈeɪn ˈɛnɪwˌʌn fɔːɹ mˈoːɹ ðɐn twˈɛnti fˈoːɹ ˈaʊɚz wɪðˌaʊt tʃˈɑːɹdʒɪŋ ðˌɛm ʌnlˈɛs ɐn ˈɑːfɪsɚ wɪððə ɹˈæŋk ʌv sˌuːpɚɹɪntˈɛndənt ɔːɹ əbˌʌv ˈɔːθɚɹˌaɪzᵻz dɪtˈɛnʃən fɚɹə fˈɜːðɚ twˈɛlv ˈaʊɚz ˈaɪ.ˈiː. θˈɜːɾi sˈɪks ˈaʊɚz tˈoʊɾəl, ɔːɹ ɐ dʒˈʌdʒ hˌuː wɪl biː ɐ mˈædʒɪstɹˌeɪt ˈɔːθɚɹˌaɪzᵻz dɪtˈɛnʃən baɪ ðə pəlˈiːs bᵻfˌoːɹ tʃˈɑːɹdʒ fɔːɹ ˌʌp tʊ ɐ mˈæksɪməm ʌv nˈaɪnti sˈɪks ˈaʊɚz; fɔːɹ tˈɛɹɚɹˌɪzəmɹᵻlˈeɪɾᵻd əfˈɛnsᵻz ɐ pˈɜːsən kæn biː hˈɛld baɪ ðə pəlˈiːs fɔːɹ ˌʌp tə twˈɛnti ˈeɪt dˈeɪz bᵻfˌoːɹ tʃˈɑːɹdʒ.