Context. T CrB (NOVA CrB 1946) is a famous recurrent nova with a recurrence timescale of 80 years. Aims. We aim to estimate the colours, luminosity, and mass-accretion rate for T CrB (NOVA CrB 1946) during and after the superactive state. Methods. We performed and analysed UBV photometry of the recurrent nova T CrB. Results. For the hot component of T CrB, we find average dereddened colours of ( U  −  B ) 0  = −0.70 ± 0.08 and ( B  −  V ) 0  = 0.23 ± 0.06, which correspond to an effective temperature of 9400 ± 500 K and an optical luminosity of 40 − 110  L ⊙ during the superactive state (2016–2022). After the end of the superactive state, the hot component became significantly redder, ( U  −  B ) 0  ≈ −0.3 and ( B  −  V ) 0  ≈ 0.6 in August 2023, and its luminosity decreased markedly to 20 − 25  L ⊙ in April–May 2023, and to 8 − 9  L ⊙ in August 2023. The total mass accreted during the superactive state from 2014 to 2023 is ∼2 × 10 −7   M ⊙ . Conclusions. This is a significant fraction of the mass required to cause a thermonuclear runaway (TNR). Overall our results support a model in which a large accretion disc acts as a reservoir with increased accretion rate onto the central white dwarf during disc high states, ultimately leading to a TNR explosion, which now seems to be imminent.