As a former refugee from Sri Lanka, M.I.A. has a rebellious, anti-establishment and politically conscious spirit that is a common thread running through all her albums, including the latest, her fifth studio offering.

Foreign Friend, Visa and Borders are commentaries on the refugee crisis which show she can be abrasive while still making catchy tunes and marshalling a dizzying array of global influences (a chirpy Tamil movie song sample is heard on Bird Song and the berimbau, a one-string bow instrument from Brazil, on Ali R U OK?).

The diversity of sounds on the album also manifests on Swords, thanks to the production chops of Dutch duo The Partysquad. The track literally uses the sounds of clashing swords, interspersed with Hindu chants, transfixing listeners with its multiculturalism.

M.I.A.'s laidback, conversational style of rap shines on Freedun, a radio-friendly collaboration with former One Direction member Zayn Malik. "I'm a swagger man/Rolling in my swagger van/From the People's Republic Of Swagistan," she boasts cheekily.

Another collaborative tune, the infectiously raw Go Off, features trippy synths courtesy of Skrillex - it is an instant club classic.

While M.I.A. has suggested in an interview with BBC Radio 1 that this album will be her last, you get the feeling that for someone who has plenty to say about the state of the world, nothing is going to keep her from music too long.

Anjali Raguraman

Even for fans of French pianist Helene Grimaud, this release may disappoint.

There are eight short movements of composers musing on the watery realm. The usual suspects are here, with Liszt's Les Jeux D'Eau A La Villa D'Este and Ravel's Jeux D'Eau depicting fountains, Debussy's La Cathedrale Engloutie (The Submerged Cathedral) and Takemitsu's Rain Tree Sketch II.

Lesser-known pieces such as Faure's Barcarolle No. 5, Berio's Wasserklavier, Albeniz's Almeria and a movement from Janacek's In The Mists are also given a hearing.

Grimaud plays these well, but the recorded sound is tinny and over-reverberant, as if to lend the music an added mystique.

Each of the pieces is separated by an interlude, entitled Water - Transition (and there are seven of them) by British composer-producer Nitin Sawhney.

These are little more than bitty morsels of recorded electronic or ambient sounds, which do little to enhance the understanding or appreciation of the actual music.

There is an 11-minute so-called bonus track Water Reflections, which reprises a few bars from earlier music and has Grimaud plainly reading out their titles and spouting a few choice words.

There are just over 50 minutes of real music in this concept album; the rest is pretentious dross.

Chang Tou Liang

The world's musical capital of piano esoteria is surely the north German town of Husum, where an annual summer festival is held to celebrate the forgotten alleys and byways of the piano repertoire.

Last year's festival again unearthed a rich vein of gems in the form of concert pieces and encores.

It takes something to omit the likes of Chopin, Schumann or Rachmaninov to present instead music by Alkan, Hummel, Harold Craxton and Mompou, performed with refinement and dedication by Yury Favorin, Florian Uhlig, Jonathan Plowright and Jonathan Powell.

What about the music of Issay Dobrowen's Poem (Powell again) or the delights of Carlos Guastavino's La Nina Del Rio Dulce from the loving fingers of Martin Jones? One is unlikely to hear these performed better anywhere else.

Improvisations and jazzed-up numbers have a prominent place, not least in Cyprien Katsaris' mash-up through Romantic operas, concertos and ballets in the manner of Liszt, which was his pre-recital preamble.

See if you can name all the tunes. Whoever remembers Alexander Zfasman, a Soviet-era bon vivant whose Fantasy On Themes By Matvey Blanter matches the syncopated best of Zez Confrey or Billy Mayerl? Played with infectious verve by American Alex Hassan, this sums up the heady spirit of one of the world's most special piano festivals.

Chang Tou Liang